Born in Toronto, Ontario. As a young man interested in the theater, he headed to New York City where he began an acting career that soon put him on the Broadway stage. There, he was one of the earliest members of Actors Equity and sat on the Council. In 1919 he was in charge of the New York headquarters during the Equity strike in which fellow Canadian and friend, actress Marie Dressler assumed a major part with him that led to her being blacklisted by the producers.
With the advent of filmmaking in New York Berton Churchill appeared in several motion pictures, and in the 1920s, following the use of sound in film, he moved to Hollywood, California. There, his powerful stage voice and commanding presence landed him numerous supporting roles, usually as the stern or pompous character with such roles as a banker, a State Governor, or a land baron. Much in demand, in more than 125 films Churchill worked for some of the great directors such as Otto Preminger, John Ford, and Frank Capra. As well, he performed with many of the most famous stars of the day such as Bette Davis, Jeannette MacDonald, Tyrone Power, Edward G. Robinson, and Will Rogers. One of Churchill's better known roles was with John Wayne in John Ford's highly acclaimed 1939 film, "Stagecoach."
In 1925, Berton Churchill helped found the Masquers club that led to him and five other actors creating the Screen Actors Guild in 1933.