American character actor specializing in villainous types, much in television. A native of New York City, Merlin studied at P.S. 15, Mangin Junior High School, Grace Church Choir School for Boys, and Stuyvesant High School. During the Second World War, he served as a torpedoman in the U.S. Navy in both Atlantic and Pacific Fleets. Upon return to civilian life, he entered the Neighborhood Playhouse School of the Theatre, became active in summer stock theatres and on Broadway, which brought him to Hollywood in 1954 for his first film Six Bridges to Cross (1955) (though Merlin had appeared in earlier television programs in New York, including a regular role on the children's program Tom Corbett, Space Cadet (1950). Merlin made a number of film appearances, primarily as a heavy. But his most frequent work was in television, where he played the near-psychotic bad guy to perfection in scores of shows, Westerns in particular. In 1958, he switched to a rare leading role, as one of the trilogy of stars in The Rough Riders (1958), a Western about three tough Civil War veterans. Merlin continued to act in occasional roles following his most prolific period of the Fifties and Sixties. In addition, in later years, as a sideline, he took work as official in the security department at a Los Angeles area airport.