Jonathan J. O'Neill

"He's an amazing man. After everything he's done, he's still modest, quite self effacing actually. He even likes people to think he's not as smart as he really is. Bottom line: He's an incredibly strong leader who's given more of himself for this program than anyone has given for... well... anything I can imagine."

- Samantha Carter

Jonathan J. O'Neill, also known as John or, most commonly, Jack, is a Lt. General, in the United States Air Force, who served seven years in the Stargate Program as a Colonel and also as the leader of the SGC's main team, SG-1.

After being released from stasis a few months after the Battle of Antarctica, Jack was eventually promoted to Brigadier General and became the new Commanding Officer of the SGC, replacing General George S. Hammond. Jack led the SGC for a year before being replaced by General Hank Landry with Jack being reassigned to The Pentagon to become the head of Homeworld Command (also called Homeworld Security). Master Bra'tac has called him "O'Neill of Minnesota", or, jokingly, "Human".

Background information
Jack O'Neill was born on October 20, 1952 in Illinois, USA and moved to Minnesota at a young age. His father-in-law described him as being an Irishman, confirming that he is of Irish descent. According to his clone, apparently he never really did embrace high school.

Despite that, and several references to his seemingly less than stellar intellect, he received an award for Academic Excellence upon his graduation from the Air Force Academy as a Second Lieutenant.

His professional life has been adventurous. He joined the United States Air Force during the Vietnam War. In 1980, he had a Parachute accident near the border of Iran and Iraq and fractured his skull. In 1982, a covert mission in East Germany went bad and Colonel John Michaels was killed. During the Gulf War, he was left behind on a mission by Colonel Frank Cromwell and spent 4 months in an Iraqi prison.

His personal history is troubled. At some point, he married Sara O'Neill and together they had a son and named him Charlie. Shortly before traveling through the Stargate for the first time, Charlie was killed while playing with his pistol and, in the aftermath of this tragedy, he separated from his wife.

1995
"Give my regards to King Tut, asshole!"

- Jack O'Neill On the first mission to Abydos, O'Neill, grieving for the accidental death of his son, Charlie O'Neill, due to him shooting himself with Jack's gun, brought a nuclear warhead, believing the mission was suicide. Ra, the Supreme System Lord of the Goa'uld Empire, discovered it and decided to send it to Earth with added Naquadah ore magnifying it by 100 times its destructive power. While there, he met Skaara, who reminded him of Charlie, but still activated the bomb. While Dr. Daniel Jackson tried to save Sha're, a local woman he had fallen in love with, O'Neill battled Ra's First Prime, finally decapitating him with the Transportation rings. Ra, however, had altered the bomb, making it incapable of deactivation. When Ra learned that the Abydonians had rebelled, he took his mothership into orbit. O'Neill, unable to deactivate the bomb, sent it up to the ship, killing Ra, but inadvertently beginning Earth's war with the Goa'uld.

1997
After the mission to Abydos, O'Neill resigned from the United States Air Force. One year later, in 1997, Major General George S. Hammond requested him to return to Stargate Command to discuss the events during the Abydos mission after Apophis and a group of his Jaffa arrived on Earth through its Stargate for a brief period of time, kidnapping Senior Airman Carol Weterings. When Hammond ordered a nuclear warhead sent to Abydos, O'Neill confessed that they did not kill the whole population, but only Ra and his ship in orbit. He requested a team be sent to the planet, but he was denied and was thrown into the Stargate Command brig. There, he met his old teammates Major Charles Kawalsky and Major Louis Ferretti. After some time, Hammond returned to the Brig and talked with O'Neill about going to the Abydos. In order to contact Dr. Daniel Jackson, who was still on the planet, O'Neill took a Kleenex box and threw it through the Stargate to Abydos. Sometime later, it was returned with the message, "Thanks. Send More".

As such, O'Neill was recalled to active duty and resumed serving with the United States Air Force, regaining his original rank of Colonel. Hammond later authorized O'Neill, Kawalsky and Ferretti to return to Abydos, along with the scientist Captain Samantha Carter. On Abydos, O'Neill was able to reunite with Daniel Jackson, however, another attack by Apophis injured Ferretti and saw Skaara and Sha're taken. The team returned to Earth with the gate address of Apophis' homeworld. Under the authorization of Hammond, O'Neill was made the leader of the team SG-1 with Carter and Jackson. They were sent off to Chulak, the homeworld of Apophis, along with SG-2 under the command of Kawalsky. SG-1 was captured by Apophis and nearly executed until O'Neill convinced Apophis' First Prime, Teal'c, to join him. O'Neill was able to acquire a staff weapon and blast a hole in the cell, and his team, along with the prisoners, were able to escape back to Earth.

1998
When Senator Robert Kinsey recommended shutting down the Stargate program, O'Neill and SG-1 hijacked the Stargate, heading to coordinates that they had found on a previous mission. There, they learned that they were on one of two Ha'taks headed to Earth, controlled by Klorel, the son of Apophis, who had taken Skaara as a host. O'Neill was forced to kill Skaara to prevent him from killing Jackson, but he was revived with a Sarcophagus. SG-1 were able to sabotage the Ha'tak, and destroy Apophis' Ha'tak in the explosion. SG-1 was hailed as heroes, and the program was allowed to remain active.

1999
While exploring P3R-272, the Ancient's Repository of knowledge was downloaded into his brain. However, Human physiology was not evolved to the point where his brain could handle that information, causing him to begin speaking Ancient and begin to die. However, his subconscious mind was able to write new addresses into the Stargate map, as well as build a generator that allowed him to gate to Othala, the Asgard homeworld. There, the Asgard erased the knowledge from his memory, told him of the Alliance of Four Great Races, and beginning the Asgard's long interest in O'Neill.

When O'Neill, Captain Samantha Carter, and Dr. Daniel Jackson were captured by Hathor, they were told that the others were dead, and that they were 78 years into the future. O'Neill was the first to discover the ruse, and located Carter and Daniel. Hathor then implanted a Goa'uld symbiote into O'Neill, but Raully was able to cryogenically freeze him, and Carter revived him. As Hathor attempted to kill Carter, O'Neill grabbed the Goa'uld Queen from behind, and threw her into the liquid nitrogen, killing her. This caused the System Lords to prepare to launch an attack on Earth, but Thor was able to negotiate Earth's entry into the Protected Planets Treaty, with O'Neill's help, beginning a deep respect between the two.

2000
"I'd have rather died myself than lose Carter. Because I care about her. A lot more than I'm supposed to."

- Jack O'Neill While on Edora, the Stargate was buried in a meteor shower, and O'Neill was trapped on the planet for over three months. There, O'Neill became close to a local woman, Laira, but after Stargate Command was able to make contact with Edora, he returned to Earth, after Major Samantha Carter spent three months building a Particle accelerator in a plan to bring him back to the SGC. He promises Laira that he will return someday; however, this never occurs. Laira also holds her belly as he leaves, implying that she is pregnant; however, this is thought to be unlikely, considering the issue is never revisited. It is also thought that Carter comes to terms with her feelings for him during this time, given her reactions to the situation.

Shortly afterwards, the Asgard and the Tollans approached Stargate Command with evidence that Earth had been stealing their technology, as well as the technology of the Nox and the Tok'ra. O'Neill and Major General George S. Hammond convinced them that the SGC wasn't responsible, but the Asgard insisted that O'Neill discover who was responsible. O'Neill "stole" a Tollan weapons scanner, and "resigned" from the military. He was approached by Colonel Harold Maybourne, who offered him a chance to acquire alien technology illegally. O'Neill, however, sent word of the Rogue N.I.D. Base to the Asgard, who then retook the technology. Rather than risk being taken by the Asgard, the rogue team follows O'Neill back through the Stargate to the SGC, where they are arrested. Hammond and O'Neill then reveal the plan to the rest of SG-1, who are somewhat offended that they weren't in on it.

When the Replicators took control of the Biliskner, Thor was forced to beam O'Neill to the vessel, to give him warning of the threat and help him destroy the ship. O'Neill requested a large amount of ordinance and weapons, and Major Samantha Carter and Teal'c beamed aboard as well. When Thor revealed that there was no way to destroy the ship easily, Carter came up with the idea to destroy it with an uncontrolled reentry. SG-1 beamed the Stargate to the ship, and was able to gate out before impact.

At the insistence of the Tok'ra Anise, O'Neill, Major Samantha Carter, and Dr. Daniel Jackson used the Atanik armbands to test their effectiveness. While they increased their natural abilities, they also affected their judgment. They hijacked the Stargate to destroy a new mothership Apophis was building, but the armbands came off halfway through the mission. However, Teal'c was able to rescue them. Later, there were concerns that O'Neill and Carter were compromised as Za'tarcs. It was only after they admitted that they had feelings for each other that they were exonerated.

When he and Teal'c became stuck in the effects of the Time loop machine, he began looking for ways to amuse himself. Knowing there would be no consequences to his actions, he spent his time golfing through the Stargate, creating pottery, biking in the base, and learning to juggle. In one loop, he gave his resignation to Major General George S. Hammond so he could take the opportunity to kiss Major Samantha Carter. When they succeeded in stopping the loop, Dr. Daniel Jackson asked him if he had done anything crazy. He gave a long look to Sam with a really sly smile on his face, before continuing to eat his breakfast. .

2001
"This is SO the last time I help someone move."

- Jack O'Neill When the NID pressured Major General George S. Hammond to step down, O'Neill allied temporarily with Harold Maybourne to locate information that would allow Hammond to return. The trail took them to Senator Robert Kinsey, revealing his very close relationship with the rogue NID members.

With the help of robotic doubles that were created by Harlan, SG-1 killed the System Lord Cronus, and acquired his Ha'tak. Using it to plan a trap for Apophis, they dialed the Stargate to P3W-451 and the Black hole absorbed some of the hydrogen from the sun around Vorash. However, an Al'kesh arrived to pick up Tanith, and Teal'c took the Death Glider they were flying in to destroy the vessel. They managed to shoot down the Al'kesh, but their Glider crashed as well. Teal'c was killed in an ambush, and O'Neill was barely saved. The jump to hyperspace caught the tail end of the supernova, which sent them and Apophis' mothership four million Light years away, to a galaxy filled with Replicators. Apophis took control of Cronus' Ha'tak, with Teal'c believing that he was once again First Prime of Apophis. SG-1 and Jacob Carter managed to destroy the Ha'tak by causing it to crash into Delmak, killing Apophis and destroying the Replicators, but Teal'c was still insistent on his loyalty. It was only with the help of Bra'tac that Teal'c's brainwashing was overcome.

2002
"You think the Asgard named a ship after you because they thought it was a cool name? Now's not the time to play dumb, you're a lot smarter than that. They saw our potential in you... because of who you are and what you've done. Humanity's potential."

- Daniel Jackson After Dr. Daniel Jackson died and ascended to save Kelowna, O'Neill retreated into himself, causing some resentment from Major Samantha Carter. He resented Jonas Quinn, and resisted his and Teal'c's attempts to allow him onto SG-1. When Anubis took Thor hostage, SG-1 agreed to help rescue him. They succeeded, but Thor was placed into a coma due to the mind probe. After Anubis tried to detonate the Stargate, and Jonas gave Carter the idea to send the gate into space with the X-302 hyperspace fighter, O'Neill performed the mission to get Carter not to do so, and allowed Jonas to join the team. After the Ha'tak that Anubis used to capture Thor appeared over Earth, O'Neill leads an away team to salvage it. When they learned that Thor's consciousness was inside the computer banks, they removed it, saving Thor but causing the vessel to self-destruct.

When researchers in Antarctica found an Ancient frozen in the ice, SG-1 and Dr. Janet Fraiser traveled down to study her. Ayiana, as the Ancient was named, was carrying a plague that infected everyone. While she healed the others, O'Neill was still sick, and Aiyana soon died afterwards. O'Neill was implanted with Kanan, a Tok'ra symbiote only because Major Samantha Carter practically begged him. After the blending, Kanan had the compulsion to rescue Shallan, the lo'taur of Ba'al, but the mission went wrong and Kanan left O'Neill's body. O'Neill was tortured by Ba'al. While Dr. Daniel Jackson approached him and offered him a chance to ascend, he refused. It was only after Yu attacked the base that O'Neill and Shallan were able to escape, but it left O'Neill with an even deeper distrust of the Tok'ra—and a long lasting animosity toward Ba'al.

2003
"O'Neill is legendary."

- Loki When Kinsey was believed to have been assassinated, O'Neill was charged with the crime, but was exonerated with the help of Malcolm Barrett and SG-1. When Harold Maybourne came to his house, claiming to have the address to a planet with Ancient weapons, O'Neill and Maybourne were transported to the planet's moon, with Maybourne attempting to locate a Furling utopia. While there, Maybourne came under the influence of a Hallucinogenic plant that caused the inhabitants to go mad and kill each other. Maybourne eventually overcame the effects, and O'Neill allowed him to retire to another planet.

Dr. Daniel Jackson later came to Jack, asking SG-1's help when Anubis was threatening Abydos. SG-1 was able to locate the Eye of Ra, and learned of the existence of a Lost City of the Ancients, but were forced to turn it over to Anubis, who threatened to destroy Abydos. Anubis destroyed the planet anyway, and started to become the dominant System Lord. While scouting Vis Uban, they found a descended Daniel, and convinced him to return to Earth. When Jonas Quinn came up with an idea to destroy Anubis' mothership, O'Neill and Major Samantha Carter flew an X-302 hyperspace fighter through the shields, and destroyed the crystals by launching a missile into the power core. Anubis took his mothership to Langara, hoping to use Naquadria to power his superweapon. O'Neill leads a team that attempted to buy time for the System Lords to destroy the vessel. The plan worked, allowing Jonas to return to Langara a hero, and allowing Daniel to rejoin SG-1.

Shortly afterwards, O'Neill was abducted by the Asgard scientist Loki, who believed that O'Neill was the key to solving their cloning problems. However, O'Neill, while advanced for the Tau'ri evolutionary chain, was not the solution for their cloning problems, and Thor placed a marker in his DNA to prevent manipulation. O'Neill was replaced by a clone who failed to mature at a normal rate, and SG-1 was able to capture Loki. After repairing the clone's DNA, a visibly angry Thor took Loki into his custody.

When Anubis created the new Kull Warriors, O'Neill leads a team to capture one for interrogation. After learning that Dr. Daniel Jackson and Dr. Bill Lee had been captured while seeking an Ancient device in Honduras, O'Neill went to rescue them.

2004
"I wish I could say I didn't owe anything to anyone. But the truth is, I wouldn't be standing here if it wasn't for the courage and support of each and every one of you. I hope I can be as good a leader as we've had in the past and as good as you deserve."

- Jack O'Neill

After locating another Ancient Repository of knowledge, O'Neill had the knowledge downloaded into his brain, in the hopes of finding the Lost City of the Ancients. After returning to Earth, however, SG-1 learned that newly inaugurated President Henry Hayes had relieved Major General George S. Hammond and replaced him with Dr. Elizabeth Weir. As O'Neill's condition began to deteriorate, SG-1 persuaded Weir to let them go by Tel'tak to Proclarush. Arriving at the planet's outpost, O'Neill activated an Ancient star map, showed a picture of Earth, and said two words: Terra Atlantus. The Lost City of the Ancients was the Lost City of Atlantis, and it was on Earth. He also took the Zero Point Module powering the outpost, and traveled to Antarctica, bypassing a fleet Anubis had brought to conquer Earth. During the Battle of Antarctica, O'Neill used the Control chair in the Antarctic outpost to activate thousands of Drone weapons, which destroyed Anubis' fleet. However, SG-1 was forced to place O'Neill in a stasis pod to prevent the Ancient knowledge from overwhelming him.

Before he erased the knowledge, Thor interfaced O'Neill's mind with the computer of the Daniel Jackson, and asked him to build a weapon to fight the Replicators. O'Neill constructed a disruptor to sever the Replicator blocks and render them inert, allowing SG-1 to rescue a captured Major Samantha Carter and save Orilla.

Back on Earth, O'Neill was promoted to Brigadier General and made commander of Stargate Command which resulted in him stepping down from his role as leader of SG-1. Despite that, Jack's first act as the SGC's commander was to promote Carter to Lt. Colonel and also make her commanding officer of SG-1.

While traveling to the Antarctic outpost, O'Neill was nearly killed when Dr. Carson Beckett launched a Drone weapon, only being saved by the flying of Major John Sheppard. At the outpost, Dr. Daniel Jackson, Dr. Elizabeth Weir, and Dr. Rodney McKay persuaded O'Neill to authorize an expedition to travel to Atlantis, in the Pegasus galaxy. Despite Weir's insistence that Sheppard, who possessed the Ancient Technology Activation gene be included, O'Neill was hesitant, citing Sheppard's record, to which Weir pointed out O'Neill's record. O'Neill tried to convince Sheppard, saying that people who don't want to go through the Stargate were "whacked". Back at Stargate Command, he denied Daniel’s request to join the expedition and wished the expedition bon voyage on a card attached to a bottle of champagne he sent through the gate.

2005
"God I miss going off-world!"

- Jack O'Neill After sending SG-1 to warn Harold Maybourne of the impending approach of Ares, they discovered an Ancient vessel designed to travel in time. As O'Neill was the only one who could fly the vessel, he went off-world to activate it. He was able to destroy Ares' Ha'tak during a battle, killing Ares and saving the people of the planet. The entire experience was rather nostalgic for O'Neill, who commented that he "missed going off world". When the adventure was over, he even said a friendly goodbye to his old rival Maybourne.

When the Replicators began an invasion of the Milky Way, O'Neill coordinated with the Rebel Jaffa, the Tok'ra, and the Asgard to mount a defense of the galaxy. He refused to help Ba'al, however, to give the Rebel Jaffa a chance to take Dakara. When the Replicators breached the Iris, O'Neill led the defense of Cheyenne Mountain, trying to stall long enough to allow Lt. General George S. Hammond to destroy the mountain. However, Lt. Colonel Samantha Carter and Jacob Carter were able to use the Dakara superweapon to destroy the Replicators in the galaxy, which also had the effect of inciting the rest of the Jaffa to rebel and bringing about the fall of the Goa'uld Empire.

When Dr. Daniel Jackson discovered that Ra possessed a Zero Point Module, they used the Time Jumper to travel back to 3,000 BC to steal it. However, the Jumper was discovered by Ra's Jaffa. SG-1 left a message to warn the future, and attempted to cause a rebellion. However, O'Neill, Lt. Colonel Samantha Carter, and Teal'c were executed, and Ra took the Stargate when he left Earth. An alternate O'Neill, Carter, and Teal'c located Daniel, ensured the Stargate was buried, and preserved the timeline (with the only noticeable exception being that the pond O'Neill fished in now had fish).

Following the collapse of the Goa'uld Empire, SG-1 disbanded itself. O'Neill was promoted to Major General and made commander of Homeworld Security (currently know as Homeworld Command), at The Pentagon, being succeeded by Major General Henry Landry as the commander of Stargate Command. Lt. Colonel Cameron Mitchell was able to reunite SG-1, however. After alerting the Ori to the presence of Humans in the Milky Way, Dr. Daniel Jackson admitted to O'Neill that he was actually scared but O'Neill reminded him that they had faced some serious threats before and come out of them out alive.

2006
"To be honest, I wouldn't mind one last jaunt through the old orifice."

- Jack O'Neill General O'Neill asked SG-1 to help Martin Lloyd in making a movie of Wormhole X-Treme!, to insure plausible deniability in case word of the Program was leaked. O'Neill also accompanied SG-1 through Mitchell's 200th trip through the Stargate, having a desire to go through it at least one more time. He convinced Landry to join them.

While testing the McKay/Carter Intergalactic Gate Bridge that Lt. Colonel Samantha Carter and Dr. Rodney McKay developed to accelerate travel between Earth and Pegasus, the Daedalus encountered live Ancients who reclaimed Atlantis. O'Neill and Richard Woolsey were sent as liaisons, as the Ancients had asked the Atlantis expedition to leave. Soon, however, the Asurans launched an attack on Atlantis, taking the Ancients by surprise.

Though O'Neill had ordered Major General Henry Landry to have Daedalus destroy Atlantis should the Ancients lose control of the city, Lt. Colonel John Sheppard, Dr. Elizabeth Weir, Dr. Carson Beckett, and McKay hijacked a Puddle Jumper to try to rescue O'Neill, Woolsey, and Atlantis. O'Neill, meanwhile, had to manually drain the water from an underwater Jumper bay to rescue them, resulting in Woolsey and himself being captured. The Replicators mind-probed him, but O'Neill actually managed to resist it due to his previous experiences, surprising the Replicators. When McKay told them his fake plan, O'Neill guessed the truth due to his years with Lt. Colonel Samantha Carter but didn't let on, his ability to resist the mind-probe protecting this from the Replicators as well.

Eventually, Sheppard, Weir, McKay, Beckett, Teyla Emmagan, and Ronon Dex were able to rig the shields to release a Replicator disruptor wave, destroying the Asurans in one fell swoop. When the team contacted the Daedalus and Colonel Steven Caldwell was unsure of them, O'Neill sarcastically addressed him, trying to convince him of the truth. O'Neill's presence and the team's insistence ultimately caused Caldwell to stand down and send a team of Marines to check out their story. On his return to Earth, O'Neill recommended that Weir be placed back in command.

2007
"Yeah. I think that went well."

- Jack O'Neill Jack was called in when Dr. Daniel Jackson was found to be a Prior. After a heated debate, he was convinced to allow SG-1 to capture an Ori warship carrying the incomplete Sangraal, hoping to send it to the Alteran Home Galaxy and neutralize the Ori. After sending Teal'c to interrogate Daniel, O'Neill finally believed his story. Daniel, however, commandeered the Odyssey and used Jack to fly him to the Supergate, as part of his plan. He needed someone to be able to work the Odyssey's controls once he left the ship and someone with authority to give an order so he chose O'Neill, the one person left he trusted. O'Neill was reluctant to trust Daniel due to the kidnapping, but exchanged banter with him.

O'Neill gave the order to the Daedalus in the Pegasus Galaxy to destroy the Stargate linked to the Supergate, allowing Daniel to dial the Supergate and send the weapon through after a moment's hesitation, apparently deciding to trust Daniel. Though they sent the Sangraal, another eight Ori warships entered the Milky Way. Before the ship could travel through the Supergate, O'Neill, at Lt. Colonel Samantha Carter's request, beamed SG-1 back aboard the Odyssey seconds before the Ori ship made the trip. Not knowing it actually worked, he witnessed the Supergate activating, sending an addition six Ori ships to the Milky Way, making the total up to eight.

It was revealed later that O'Neill and SG-1's efforts had succeeded in destroying the Ori.

2008
"Never in the history of boredom has anyone been more bored than I am right now."

- Jack O'Neill

After capturing the final Ba'al clone, O'Neill attended the Extraction Ceremony on the Tok'ra homeworld with SG-1. The ceremony went through and the final Ba'al clone was killed and Vala Mal Doran stayed behind to help Ba'al's host cope with the extraction because she knew what he was going through as a former host herself. He and the rest of the team went to lunch on O'Neill.

2009
"Second guessing a decision is a waste of time."

- Jack O'Neill When Earth was under siege by the Super-hive, O'Neill ordered Lt. Colonel John Sheppard to return to Earth to use the Control chair.

Sometime before or after the Wraith attack on Earth, Jack O'Neill was promoted to Lt. General.

For a brief period, O'Neill was placed in command of Atlantis by the International Oversight Advisory when they were contemplating allowing it to remain on Earth, but he used this authority to arrange for the necessary equipment to be provided to the city so that it could make the necessary repairs to return to Pegasus.

O'Neill, along with Dr. Nicholas Rush, recruited Eli Wallace into the Stargate program. He later had a conversation with Colonel Samantha Carter regarding the events of the attack on Icarus after the planet was destroyed. It wasn't until Rush, in Dr. Bill Lee's body, briefed him on the situation that he learned the Icarus personnel had gone through the Stargate to the Destiny.

Later, Colonel Everett Young, while in the body of Colonel David Telford, briefed O'Neill a second time of the current situation and O'Neill, after putting Young in charge of the ship, offered some words of encouragement.

According to O'Neill, he offered Colonel Everett Young the position of commander of the Destiny expedition before he offered it to Colonel David Telford, but Young turned him down the first time.

O'Neill (along with Dr. Daniel Jackson) helped Colonel Everett Young out with trying to find out if Colonel David Telford was a Lucian Alliance spy. When it was later found out that Telford was the spy, O'Neill made his first trip to the Destiny using the Long-range communication device to help Young with the interrogation. He swapped bodies with Cpl. Marsden.

O'Neill gave Colonel Samantha Carter the order to attack the Lucian Alliance outpost. After the attack failed, he gave Colonel Everett Young a dressing down for failing to vent the atmosphere of the Destiny Gate room when the Lucian Alliance gated to the Destiny. He also told Young that if he wasn't up to it he would be replaced by someone who would get the job done.

Alternate realities

 * In an alternate reality, Jack O'Neill was a Brigadier General and the commanding officer of the SGA in 1998. As was the case with his counterpart in our reality, he was part of the original team which traveled through the Stargate to Abydos in 1995 with the intention of detonating a nuclear weapon. At the time, he was willing to commit suicide as his son Charlie had recently died after accidentally shooting himself with Jack's personal gun. When the Goa'uld invaded Earth and he discovered the location of Chulak from the Dr. Daniel Jackson of our reality, he sent a nuclear weapon through the Stargate to attempt to halt the attack. He did not believe the Jaffa were worth salvaging a relationship with. This led to his death when he tried to turn Teal'c from his service to Apophis using footage of his counterpart from our reality provided by Daniel. Unfortunately, this resulted in Jack dying with Teal'c personally killing Jack in revenge for Jack sending the bomb to Chulak that had killed Teal'c's wife and young son. The Jack O'Neill from this reality was colder and more militaristic than his counterpart in our reality, purely due to the fact that he had never met Daniel with Daniel helping Jack to mellow and ultimately grow into a better person. He was engaged to Dr. Samantha Carter at the time of his death, indicating that he and Sara O'Neill had divorced by then. It should also be noted that he had a permanent scar on his left eyebrow which the main timeline O'Neill would receive in the Season 2 episode, "1969". 
 * In another alternate reality, Jack O'Neill had been married to Dr. Samantha Carter for a year by 1999. He died in the Goa'uld invasion of Earth, having been killed by Teal'c, the First Prime of Apophis, in front of his master as well as Sam. His death had a huge emotional impact on his wife. It seems that he was very similar to his counterpart in our reality. It appears that he also frequently used the phrase "for crying out loud" and would not "have a clue" what to tell a woman in the middle of an emotional crisis. The Jack of our reality asked her how she could marry "such a loser." Major Charles Kawalsky considered Jack his best friend. Consequently, he reacted angrily upon seeing the Teal'c of our reality at Stargate Command, though he eventually came to trust him.
 * In another alternate reality, Jack O'Neill was still in command of Stargate Command in 2006 while the version of SG-1 under his command consisted of Daniel Jackson, Cameron Mitchell, Janet Fraiser and Martouf/Lantash. His world was in the process of being attacked by the Prior virus at the time that his SG-1 was accidentally sent to our reality.
 * In another alternate reality visited by Lt. Colonel Samantha Carter in 2007 in which Anubis' attack forced the Stargate Program into the public eye, Jack O'Neill's fate was never made clear, although it is possible that he was never removed from the Ancient stasis pod in the Antarctic outpost.

Alternate timelines

 * In an alternate timeline, Colonel Jack O'Neill was retired and living in his cabin in 2010. He was visited by Samantha Carter when she and Doctor Janet Fraiser discovered the Aschen had sterilized most of the Earth's population. They, Doctor Daniel Jackson and Teal'c developed a plan to prevent this from happening, but they wanted O'Neill's help. At first, he was reluctant, but later joined them. When the plan was put into action, he was the first one to attempt to get a note through the Stargate. He was killed by the automated defense system before reaching it.
 * In a possible future, the Aschens' attempt to get revenge against the Tau'ri resulted in the creation of a pathogen that destroyed virtually all life on Earth and spread throughout the Stargate network; by 2033, Commander Jack O'Neill was the last living member of Stargate Command, and had a daughter, Jade O'Neill (Her mother was not identified). With the aid of a Reetou ally and Ancient teleportation pods, Commander O'Neill and Jade travelled back in time to prevent the alliance that led to the Aschen Pathogen contaminating Earth, resulting in him meeting his younger self and Daniel. The two O'Neills initially argued about their methods- Commander O'Neill having resorted to the 'whatever-it-takes' approach that Jack had abandoned over his years in the SGC, willing to bomb the treaty negotiations and kill even Tealc and Carter just to save Earth- but reconciled in time to destroy the Aschen ship from the inside before escaping using an Ancient teleportation pod. Commander O'Neill and Jade later returned to the future, accepting whatever would happen to them in favor of a superior future (Stargate SG-1: Relativity)
 * In an alternate timeline accidentally created by SG-1 in which the Stargate Program never existed, Colonel Jack O'Neill was retired and owned his own boat called Homer. In 2005, he went to Chulak with Doctors Daniel Jackson and Samantha Carter to recruit Teal'c. They traveled back to ancient Egypt to fix the timeline. As he and Sam worked alone in the Puddle Jumper, Jack told her that he found her attractive, but she replied that she liked Daniel, whom Jack thought might have been gay. A short while later, however, when thinking they were going to be killed, she kissed him, saying that she had lied and that she had only wanted to take her time to get to know him better. He then cut off her rambling explanation by kissing her again. When Daniel told them over the radio that it was safe to come outside, Jack replied that they would be a bit longer; they then kissed again, sparks flew from the broken machine in the background, and Sam remarked that she could "fix that.". He and Sam later began a relationship and had a daughter named Eleanor O'Neill, who was named after Sam's late mother Eleanor Carter.
 * In the alternate timeline created by Ba'al in which the Stargate Program also never existed, Jack O'Neill was a Colonel in the United States Air Force and Charlie O'Neill was still alive in 2008. Prior to history being altered, Jack was killed by the original Ba'al as he attempted to escape back to Earth. Because of SG-1 passing through a wormhole on their way to Earth, they were unaffected by the changes in the timeline were able to restore the correct course of the timeline, leading to Jack not being killed by Ba'al's clone and continuing on with the Extraction Ceremony.

Personality and traits
"You have a thing for The Simpsons, fishing, Mary Steenburgen, the color peridot, and you're a terrible ping pong player!"

- Joe Spencer Jack has a very dry sense of humor (which he acquired after his mission to Abydos, before that he was a quiet and serious man) and is impatient with complicated explanations. However, in a conversation with Lt. Colonel Samantha Carter, he explains that he is worried about her because she has not tried to baffle him with scientific babble for a few days. When he is asked a scientific question he doesn't know the answer to, he often jokingly answers with "magnets," or some variation of the term. As stated by Cassandra Fraiser, Jack pretends he's not as smart as he really is. .

Jack has a tendency to not lock his house when leaving, which has caused some unwanted visits. Jack O'Neill also naturally possesses the Ancient Technology Activation gene. His service number is 69-4-141. O'Neill loves cake, often referencing it when formal situations or events arise with the phrase "I hope there's cake". He goes out of his way on several occasions to make sure cake is being served to celebrate a particular event. His favorite color is peridot. If he could have dinner with one person in the world it would be Mary Steenburgen. He used to be a cigarette smoker but quit during the mission to Abydos. His favorite television show is The Simpsons. In his free time, Jack enjoys fishing in the lake next to his cabin in Minnesota. After several failed attempts to get Carter to come with him, he finally succeeded shortly after the fall of the Goa'uld Empire. He also enjoys Boxing, Chess, Golf and Ping pong.

The Asgard showed great fondness toward him, and likewise O'Neill showed great fondness towards the Asgard and in particular to Thor. Loki even stated that: "O'Neill is legendary" hinting at the Asgard's view of him. To them, he led his people through the galaxy and proved to them that the Tau'ri were well on their way to be the "Fifth Race". He also downloaded, twice, the knowledge of Ancients and through this created the Replicator disruptor which saved their planet. When Earth was accused of stealing over Asgard, Nox and the Tollan's technology, the Asgard chose him alone to prove his people weren't the culprits.

Jack also has a tendency to give people, usually Goa'uld, nicknames. Included are "T" for Teal'c, "B" for Ba'al, "Zippy" for Zipacna, "Cammy" for Camulus, and Marty for Martouf.

Sara O'Neill
At some point, he married Sara O'Neill and together they had a son and named him Charlie O'Neill. Shortly before traveling through the Stargate for the first time, Charlie was killed while playing with his pistol and, in the aftermath of this tragedy, he separated from Sara O'Neill.

Kerry Johnson
He had a relationship with CIA Agent Kerry Johnson, but she felt there was something deeper between him and Lt. Colonel Samantha Carter. Kerry told him to retire but he didn't take her advice. She goes on saying they were making big error if they let military rules stop their feelings.

Samantha Carter
He has feelings for Colonel Samantha Carter that seem to be reciprocal; they were once both forced to admit it to avoid being labeled as Za'tarcs. Because this kind of relationship is forbidden in the United States Air Force, he has never pursued a relationship with her, keeping well within the rank border. He even encouraged her during her engagement to Pete Shanahan. When he and Teal'c were stuck in the effects of the Time loop machine and had the opportunity to do whatever they wanted with no fear of the consequences, one of the things he did was to give his resignation to Major General George S. Hammond. When Carter asked him why, he replied, "So I can do this." Then he pulls her into a long kiss, which she evidently reciprocated. Jacob Carter has hinted at knowing their feelings, as have Teal'c and Major General George S. Hammond. When a wedding was proposed by Vala Mal Doran in her search for an ending scenario for a Wormhole X-Treme! movie, neither of them answered.

Teal'c
Jack's friendship with Teal'c is one long-standing friendship that has lasted for over ten years and continues to this day.

The two men met each other in grim circumstances during a mission to Chulak where SG-1 later became Apophis's prisoners. After the System Lord had chosen new people to be possessed by the Goa'uld he called his "children", Apophis then ordered for the prisoners to be killed which caused mass panic.

During the rioting, Jack appealed to Teal'c- who had already begun to believe that his God was not a true God- insisting to Teal'c that he could save the people with Teal'c's help. Despite having heard many make that promise before and fail to deliver, Teal'c turned against his fellow Serpent Guards and chose to side with the Tau'ri, noting that Jack was the first person he had met who he believed could fulfil that promise. With Jack's help, he and Teal'c were able to kill most of the guards before Jack launched a staff weapon blast at the wall, creating a hole which gave everyone a chance to escape.

Although Teal'c was reluctant to go, Jack eventually convinced him to join them and thus, their friendship was born. Teal'c also assisted Jack and SG-1 as well as SG-3 long enough for Doctor Daniel Jackson and Captain Samantha Carter to bring most of the remaining survivors back to Earth. Although Teal'c was later met with some distrust upon arriving at the SGC for the first time, he soon proved his loyalty and was permitted to become part of SG-1.

When Teal'c once stated he was a brother to him, Jack reminded him that Teal'c was twice his age; Teal'c conceded that he was a very young brother, then, though it had no importance as he was trying to comfort him while Major Samantha Carter was missing.

Over the years, Teal'c and Jack's friendship has continued to grow strong with both men often willing to help the other in times of despair.

Daniel Jackson
Jack and Daniel have a great respect for one another, despite their differences. Ever since the mission to Abydos, they have been on a first name basis, even after Jack was promoted. Although their relationship became more strained after Jack lied to Daniel during his undercover operation and ignored Daniel's advice during a crucial mission, in the aftermath of Daniel's Ascension they became closer once more, Daniel commenting that he was essentially Jack's best friend when talking with an alternate version of Jack.

George Hammond
General Hammond has long had Jack's trust and respect. While Jack can be somewhat of a renegade, he's careful to respect Hammond as his superior. Occasionally Jack will disregard Hammond's orders, as he is the man on the ground, but this is never out of spite or disrespect, but simply a greater understanding of the situation in real-time. After Hammond's promotion to Lieutenant General and installation as head of Homeworld Command, Jack was promoted to Brigadier General and given Hammond's command of the SGC. Jack was reluctant the entire way through, going so far as to write Hammond a letter tendering his resignation and stating Hammond was a better leader than he. Jack was subsequently delighted to find Hammond had let himself into his office and sat in his chair. Though he was disappointed to find out Hammond was merely there to recruit Daniel Jackson into a mission he was personally leading to the Pegasus Galaxy to make contact with the Atlantis Expedition, and also disappointed that Hammond would be requisitioning his desk chair. (SG1: "Zero Hour", "Prometheus Unbound")

Jacob Carter
Jack and Jacob have always had a mutual respect for each other, despite their superior/subordinate relationship within the Air Force. Jacob recognized Jack's experience and expertise, and often deferred to his judgment in strategic matters. The presence of Selmak, while distasteful to Jack, proved to be beneficial to their friendship as it afforded them more opportunities to work together in Tok'ra/Tau'ri operations. Jack was always pleased whenever the Tok'ra sent Jacob to Earth. Jacob was always aware of the mutual feelings between Jack and his daughter Samantha, as he clearly let on after he had met Sam's fiancé Pete. Jack was genuinely saddened by Jacob and Selmak's death and made a special effort to comfort Samantha in Jacob's final hours. (SG1: "Secrets", "The Tok'ra Part 1", "The Tok'ra Part 2", "Reckoning Part 1", "Reckoning Part 2", "Threads").

Service Awards and Decorations
Over the course of his military career, Jack O'Neill has received a number of awards and decorations for his service in the United States Air Force.


 * , w/3 bronze oak leaf clusters (4 awards)
 * , w/2 bronze oak leaf clusters (3 awards)
 * , w/2 bronze oak leaf clusters (3 awards)
 * , w/2 bronze oak leaf clusters (3 awards)
 * Air Force Outstanding Unit Award, w/Valor and 3 bronze oak leaf clusters (4 awards)
 * , w/1 bronze oak leaf cluster (2 awards)
 * , w/1 bronze service star (2 awards)
 * , w/1 bronze service star (2 awards)
 * , w/3 bronze oak leaf clusters (4 awards)
 * , w/2 bronze oak leaf clusters (3 awards)
 * , w/2 bronze oak leaf clusters (3 awards)
 * Air Force Outstanding Unit Award, w/Valor and 3 bronze oak leaf clusters (4 awards)
 * , w/1 bronze oak leaf cluster (2 awards)
 * , w/1 bronze service star (2 awards)
 * , w/1 bronze service star (2 awards)
 * , w/3 bronze oak leaf clusters (4 awards)
 * , w/1 bronze service star (2 awards)
 * , w/1 bronze service star (2 awards)
 * , w/3 bronze oak leaf clusters (4 awards)
 * , w/3 bronze oak leaf clusters (4 awards)
 * , w/3 bronze oak leaf clusters (4 awards)

Other versions

 * Jonathan O'Neill
 * Jack O'Neill (Unity)
 * Jack O'Neill (android)

Behind the scenes

 * In the original movie, this character's last name is spelled "O'Neil", with one L. Since O'Neil in the movie and O'Neill in the series are obviously supposed to be the same person, his name is spelled in this article the same way as in SG-1/Atlantis canon, even when speaking about the events of the movie. See Stargate canon for more details about this discrepancy.
 * Along with Dr. Daniel Jackson, Jack O'Neill is one of only two characters to appear in the original Stargate film, Stargate SG-1, Stargate: Atlantis and Stargate Universe.
 * Jack is one of only eight characters to appear in all three series, the others being Daniel Jackson, Samantha Carter, Rodney McKay, Richard Woolsey, Bill Lee, Walter Harriman, and Kevin Marks.
 * Along with Daniel Jackson, Samantha Carter, Teal'c, George S. Hammond, Walter Harriman and Sylvester Siler, he is one of only seven characters to appear in all ten seasons of Stargate SG-1.