Sidney Blackmer had planned to study law at the University of North Carolina--Chapel Hill, but football and amateur theatricals held more interest for him. Heading east to make his fortune as an actor, Blackmer accepted day work at various film studios in Fort Lee, New Jersey, reportedly appearing in the pioneering Pearl White serial The Perils of Pauline (1914). After making his Broadway bow in 1917, Blackmer served as a lieutenant in World War I. His starmaking stage role was the title character in 1921's The Mountain Man. Eager to have a go at all branches of entertainment, Blackmer sang on radio in the 1920s, and participated in the first experimental dramatic presentations of the Allen B. DuMont television series. In films, Blackmer was usually cast as a smooth society villain, e.g. "The Big Boy" in the 1931 gangster flick Little Caesar. He appeared in both sinister and sympathetic roles in a handful of Shirley Temple pictures, and also starred as pulp-novel detective Thatcher Colt in the 1943 programmer The Panther's Claw. Blackmer is best remembered for his portrayals of President Theodore Roosevelt in over a dozen films, including This is My Affair (1937) and My Girl Tisa (1947). In 1950, Blackmer won the Tony award for his portrayal of the drink-sodden "Doc" in the William Inge play Come Back Little Sheba; he later created the role of Boss Finley in Tennessee Williams' Sweet Bird of Youth. For several years, Blackmer served as the national vice president of the Muscular Dystrophy Association. Sidney Blackmer was married twice, to actresses Lenore Ulric and Suzanne Kaaren.