Waldo Brian Donlevy (February 9, 1901 – April 6, 1972) was an American actor, noted for playing dangerous tough guys from the 1930s to the 1960s. He usually appeared in supporting roles. Among his best-known films are Beau Geste (1939), The Great McGinty (1940) and Wake Island (1942). For his role as the sadistic Sergeant Markoff in Beau Geste, he was nominated for the Academy Award for Best Supporting Actor. He starred as U.S. special agent Steve Mitchell in the radio/TV series Dangerous Assignment.