As he was preparing to deploy to the war in Korea, his orders were changed, and he spent the rest of his time in the Marine Corps, from 1951 to 1953, teaching communication in the Instructors' Orientation Course.

[4] Studying with the Actors Studio,[5] Dillman spent several seasons apprenticing with the Sharon, Connecticut Playhouse before making his professional acting debut in The Scarecrow in 1953.

[6] Dillman first performed in a Broadway play as part of the U.S. premiere cast of Eugene O'Neill's Long Day's Journey into Night in November 1956.

In 1957, Katharine Cornell cast him in a Hallmark Hall of Fame television production of Robert E. Sherwood's Pulitzer Prize winning 1940 play, There Shall Be No Night.

[11] After making the movie Circle of Deception (1960) in London, Dillman was reunited with Welles, Fleischer and Zanuck for Crack in the Mirror (1960), filmed in Paris.

Back in Hollywood, Fox cast Dillman in support of Yves Montand and Lee Remick in Sanctuary (1961).

[18] He appeared in occasional movies during this period, including A Rage to Live (1965), Sergeant Ryker (1968), and The Bridge at Remagen (1969).

Lovecraft's 1926 story, Pickman's Model, presented as the opening act of a December 1971 Night Gallery episode.

[20] In 1970 Bradford in the role of a U.S. Army captain starred with Brian Keith and Tony Curtis in the TV film Suppose They Gave A War and Nobody Came.

He also starred as the sadistic hunter Michael Sutton in "The Snare", the ninth episode in the third season of The Incredible Hulk (initially aired on December 7, 1979).

[19] His film work included Escape from the Planet of the Apes (1971), The Way We Were (1973), Gold (1974), Bug (1975), The Enforcer (1976), The Swarm (1978), Piranha (1978), Sudden Impact (1983), and Lords of the Deep (1989).