About Jack O'Neill
Jonathan J. "Jack" O'Neill is a fictional character in the Metro-Goldwyn-Mayer military science fiction franchise Stargate, primarily as one of the main characters of the television series Stargate SG-1. Richard Dean Anderson played O'Neill in all the Stargate media from 1997, when he took over the role from actor Kurt Russell, who portrayed the character in the original Stargate film in 1994. O'Neill and Daniel Jackson are the only two characters to appear in both the original film and all three live-action Stargate television series.
Biography source:
Wikipedia
