Born Sabino Tomas Gomez in New York City, New York, Gomez began his acting career in theater during the 1920s and was a student of the actor Walter Hampden. He made his first film Sherlock Holmes and the Voice of Terror in 1942 and by the end of his career had appeared in sixty films.

He received a nomination for an Academy Award for Best Supporting Actor for his performance in the film Ride the Pink Horse (1947). Directed by and starring Robert Montgomery, it was later used as the basis for an episode of the same name for the television series Robert Montgomery Presents in which Gomez reprised his role.

His other film roles include Who Done It? (1942), Key Largo (1948), Force of Evil (1948), The Conqueror (1956) and his final film Beneath the Planet of the Apes (1970). A frequent performer on television, Gomez also appeared in guest roles in such series as The Twilight Zone, Route 66, Dr. Kildare, Mr. Ed, Burke's Law, The Virginian, It Takes a Thief, Bewitched and Gunsmoke.

Gomez had many notable stage roles, in Broadway and off-Broadway shows, and replaced Leo McKern as Thomas Cromwell in the original Broadway run of A Man for All Seasons.

Thomas Gomez died in Santa Monica, California from injuries sustained in a car accident and was interred in the Westwood Village Memorial Park Cemetery in Los Angeles.