Leo White started in comedy on the boards of English music hall in the late 1890's. He accompanied theatrical producer Daniel Frohman (later a partner of Adolph Zukor in Famous Players Lasky) to Hollywood in 1910. From 1914, he appeared in Essanay comedies and filmed the 'Sweedie' series with Wallace Beery. He then became a regular supporting player in Charles Chaplin's films at Essanay and, later Mutual, playing dapper, moustachioed continental (particularly French) villains and pompous aristocrats. That image remained with him, as he was contracted by Essanay to play the comic foil to their new French star comedian Max Linder.

White's major dramatic film credits of the silent period included Blood and Sand (1922) with Rudolph Valentino and the biblical epic Ben-Hur: A Tale of the Christ (1925). He successfully made the transition to talking pictures and had supporting roles in two Marx Brothers comedies, Monkey Business (1931) and the classic A Night at the Opera (1935), as well as playing a barber in Chaplin's The Great Dictator (1940). In the years just prior to his death, he worked as an extra in several films for Warner Brothers.