His father, Del'nor, had once been spared by Teal'c when Apophis had ordered his death. Del'nor in turn had followed Bra'tac's rebellion and sought to give his son freedom from false gods by searing the Jaffa mark from Rak'nor's forehead.
However, when his family was killed by Apophis, Rak'nor saved himself by declaring his loyalty to Apophis as his god. Rak'nor grew up with the belief that the Goa'uld were gods, denounced his father and entered the service of Heru'ur. (SG1: "The Serpent's Venom")
Years later, Rak'nor betrayed Teal'c on Chulak and turned him over to Heru'ur, to be tortured by Terok, however, after witnessing Teal'c's conviction in the face of torture, Rak'nor had a change of heart. He rescued Teal'c and helped him to escape from Heru'ur's mothership, eventually espousing Teal'c's belief that the Goa'uld are false gods, and joining the Jaffa Rebellion. (SG1: "The Serpent's Venom")
Rak'nor was among the Jaffa refugees who fled to the Tau'ri's Alpha Site to continue the Jaffa Rebellion. He accused the Tok'ra of killing Artok but after it was discovered that Anubis' Ashrak was responsible he helped secure the Stargate until the Ashrak was killed by Bra'tac. (SG1: "Allegiance")
When Bra'tac and Rya'c were taken prisoner in a death camp on an unknown Goa'uld world, Rak'nor assisted SG-1 to identify the planet as Erebus, and he accompanied SG-1 on the rescue mission. He and Teal'c were captured, beaten, and tortured, however he survived to help liberate the death camp of Erebus and to continue to fight for the Rebel Jaffa movement. (SG1: "Orpheus")
After the fall of the System Lords at the Battle of Dakara, Rak'nor helped to build the new Free Jaffa Nation. Like Teal'c, he feared Gerak's rise to power, and he cooperated with Teal'c and Bra'tac in establishing a new government of free Jaffa. Rak'nor currently serves as Teal'c's proxy on the Jaffa High Council. (SG1: "Avalon, Part 1")