- See Jefferies for other articles with titles that contain, either by relationship or by coincidence, this character's surname.
He was still working on the Program when the NX-01 Enterprise was launched in 2151; he had occasion to argue with Captain Jonathan Archer over how heavily armed the NX-class should be. Archer was against increased armament, but after the Xindi crisis began to think Jefferies may have been right. (ENT episode: "Home")
By 2163, Jefferies had been promoted to commodore serving in the Federation Starfleet and was working on a plan to integrate the newly formed fleet for new designs, such as the Wasp class and Bonaventure class, to incorporate the best from every species' technology. (ENT novel: A Choice of Futures)
- His full name was given as "George William Jefferies" in the TOS novel: Home is the Hunter and he was called "George" in ENT novel: Beneath the Raptor's Wing.