A distinguished member of Broadway's famed Group Theater, with whom he appeared in Casey Jones (1938) and Night Music (1940), Clancy Cooper entered films with Warner Bros. in 1941. But despite his distinctive theater pedigree, Cooper's busy screen career proved middling at best and he mainly played bit roles. A notable exception came in the 1944 serial Haunted Harbor, as one of hero Kane Richmond's two sidekicks. A veteran of more than 100 feature films, the veteran actor went on to also embrace television, appearing in over 200 episodes in shows such as The Lone Ranger, Adventures of Rin Tin Tin, Gunsmoke, Twilight Zone, Maverick, Dr. Kildare, and The Wild Wild West. Married to novelist Elizabeth Cooper, Clancy Cooper died of a heart attack while driving in Hollywood.