Mason Alan Dinehart Sr. (born Harold Alan Dinehart; October 3, 1889 – July 18, 1944) was an American actor, director, writer, and stage manager.

[1] He left school to appear on stage with a repertory company and had no screen experience when he signed a contract with Fox in May 1931.

Dinehart co-wrote and starred in the Broadway play Separate Rooms, which opened on March 23, 1940 at the Maxine Elliott Theatre and ran for 613 performances.

[2] Dinehart's likeness was drawn in caricature by Alex Gard for Sardi's, the New York City theater district restaurant.

[3] Dinehart's second son, Mason Alan Dinehart, was cast in several 1950s television series, including the role of a young Bat Masterson in the ABC/Desilu Studios western, The Life and Legend of Wyatt Earp, starring Hugh O'Brian in the title role.