[2] He was known for playing the role of Brody in the American crime drama television series The Lawless Years.

After serving in the army during World War II, Trumbull studied at the Pasadena Playhouse, graduating in 1950.

He guest-starred in television programs including Gunsmoke, One Day at a Time, Diff'rent Strokes,[1] M*A*S*H, Mister Ed, The Golden Girls,[1] Tales of Wells Fargo, The Andy Griffith Show, Mannix, The Doris Day Show and Highway Patrol.

[1] Trumbull also appeared in over ninety episodes of the variety television series The Carol Burnett Show.

He also appeared on the episode "Cellmates" of Mama's Family playing a police officer who gets assaulted by Eunice.