Gary Lockwood was born John Gary Yurosek in Van Nuys, California to John and Margaret Emma (Kiel) Yurosek . He attended UCLA 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 The Case of the Romantic Rogue (1959). Two series came early in his career, ABC's Hawaii-set Follow the Sun (1961) (1961-62) as an adventurous magazine writer in Honolulu. In 1961, he appeared as a rodeo cowboy in love with an 18-year-old singer (played by Tuesday Weld) in ABC's Cherie (1961). He then starred with Lloyd Bridges in My Daddy Can Lick Your Daddy (1963). In 1964, he starred as a young U.S. Marine lieutenant in the NBC series, The Lieutenant (1963). He then starred in another NBC television series, Kraft Mystery Theater (1961), opposite Sally Kellerman (with whom he would later appear in the second Star Trek (1966) pilot, Where No Man Has Gone Before (1966)) as "Lt. Cmdr. Gary Mitchell", and Kellerman as the ship's psychiatrist, "Dr. Elizabeth Dehner", who both develop destructive super powers.
In 1966, he guest-starred in the episode, Reunion (1966), of ABC's The Legend of Jesse James (1965). That same year, he appeared on Day of Thunder (1966) of the NBC's drama The Long, Hot Summer (1965), as well as appearing as "Jim Stark" in the two-part episode "The Raid" of CBS's Gunsmoke (1955).
He co-starred with Stefanie Powers (his wife at the time) in the episode, Love and the Phone Booth/Love and the Doorknob (1969), of ABC's Love, American Style (1969). In 1968, he was cast as the co-star in director Stanley Kubrick's legendary 2001: A Space Odyssey (1968), starring as "Dr. Frank Poole". In 1983, he made a guest appearance as "Alex Carmen" in the Hart to Hart (1979) episode, Emily by Hart (1983).
Between 1959 and 2004, he had roles in some forty theatrical and made-for-TV features and made almost eighty TV guest appearances, including several as a villain on CBS-TV's Barnaby Jones (1973).
