Throughout his 35-year career in film, Hadley was cast as both a villain and a hero of the law, in such movies as The Baron of Arizona (1950), The Half-Breed (1952), Highway Dragnet (1954) and Big House, U.S.A. (1955), and narrated a number of documentaries. In films, he starred as Zorro in the 1939 serial Zorro's Fighting Legion.