Major Lorne served under Colonel Edwards of SG-11 as part of the naquadah mining operation on P3X-403. He helped to coordinate the surveys and analyses of the area, and he headed one of the search parties that located Lieutenant Ritter after he had been captured and killed by the native Unas.
Lorne later joined the expedition to Atlantis under Dr. Elizabeth Weir, and he has been based off-world in the Pegasus Galaxy. When Colonel Carter was drawn through an inter-universal bridge into an alternate reality, she recognized immediately that something was wrong when Major Lorne, stationed at the SGC rather than at Atlantis, addressed her as "Major" and identified himself as the leader of SG-1. Lorne cooperated in Carter's debriefing and supported her efforts to save the planet and return to her own reality.
Portrayed by: Kavan Smith