Jack O'Neill is a USAF colonel (later brigadier general, major general and then lieutenant general) who led the original mission through the Stargate in Stargate. He is played by Kurt Russell in the film, and by former MacGyver actor Richard Dean Anderson in a regular role in seasons 1–8, and in a recurring role in seasons 9–10, also Michael Welch played young Colonel O'Neill in episode "Fragile Balance". He also appears in Stargate: Continuum, and in seasons 1 and 3 of Stargate Atlantis. Colonel O'Neill is the leader of the SG-1 team in the first seven seasons, and takes charge of Stargate Command after his promotion to brigadier general at the beginning of season 8. He is promoted to major general at the beginning of season 9, and is reassigned to Washington, D.C., then makes sporadic appearances in the final episodes of season one of Stargate Universe.
