Pat O'Brien (1899-1983) was an American actor, best known for his roles as the Irish-American "everyman." His film career flourished in the 1930s and 1940s, specializing in upright yet forthright characters: priests, policemen, military officers, and journalists. He was renowned for his ability to portray authoritarian yet sympathetic figures.

His best-known films include The Front Page (1931), as journalist Hildy Johnson; Angels with Dirty Faces (1938), opposite James Cagney as Father Jerry Connolly; and Knute Rockne, All American (1940), where he played the legendary football coach. He was often paired with James Cagney, forming one of Hollywood's most iconic acting duos. His style was characterized by direct and honest acting.