Gary Lockwood was born in Van Nuys, California. He attended the University of California at Los Angeles on a football scholarship. He began his career as a movie stuntman, and a stand-in for Anthony Perkins, prior to his acting debut in 1959 in an uncredited bit role in Warlock (1959). He also appeared as a police officer in Perry Mason: The Case of the Romantic Rogue (#2.17) (1959).

Two series came early in his career, ABC’s Hawaii-set Follow the Sun (1961), in 1961-1962, cast him in as an adventurous magazine writer in Honolulu. In 1963 Lockwood was cast opposite Elvis in It Happened at the World’s Fair as his good friend Danny Burke In 1964, he then scored the leading role as a young U.S. Marine lieutenant in the NBC series, The Lieutenant (1963), which was produced by Star Trek (1966) creator, Gene Roddenberry. Roddenberry would then cast Lockwood again in the second Star Trek (1966) pilot, Star Trek: Where No Man Has Gone Before (1966), as “Lt. Cmdr. Gary Mitchell”. It was this role that would send him down the sci-fi path.

In 1968, he was cast as the co-lead in director Stanley Kubrick’s legendary Sci-Fi film, 2001: A Space Odyssey (1968), starring as “Dr. Frank Poole”. Between 1959 and 2004, he had roles in some forty theatrical and made-for-TV features and made almost eighty TV guest appearances on shows such as Murder She Wrote, The Six Million Dollar Man, The Bionic Woman, Charlies Angels, TJ Hooker and MacGyver.