Actor. He was known for his tough Irish character roles, often playing an Irish cop, an Irish priest, or an Irish descended soldier. Born in Milwaukee, Wisconsin, he was a boyhood friend of Spencer Tracy, with whom he attended school, and with whom he joined the United States Navy during World War I. They entered a career in action, and O'Brien played vaudeville as a dancer before moving on to the Broadway stage in the early 1920s. Although some biographies report that O'Brien's first movies were in 1919, these are hard to confirm since there was another actor that used the name Pat O'Brien back in those days. His first major role was that of reporter 'Hildy Johnson' in "The Front Page" (1931). He would freelance is first few movies, but in 1932, he signed on with Warner Brothers Studio, for the next seven years. During this period, he made his best films with his close friend, actor James Cagney, often playing the role of a responsible mature friend to Cagney's cocky, womanizing rebel. Their best roles together were the movies "Angels with Dirty Faces" (1938), and "The Fighting 69th" (1939). Unlike many actors who fought the studios over salary and roles, O'Brien was considered a team player who accepted his assignments without protest. He is perhaps most remembered for his starring role in "Knute Rockne, All American" (1940), who plays the famous Notre Dame Football Coach who urges his players to win the big game for the George "The Gipper" Gipp, played by actor Ronald Reagan. For the rest of his life, he would be asked to repeat the famous locker-room pep talk at dinners and other public functions. In 1940, O'Brien left Warner Brothers to freelance, taking mostly leading roles and occasional supporting roles. His best roles in this period were with RKO, in "Having a Wonderful Crime" (1945), "Fighting Father Dunne" (another Irish priest role – 1947), and "The Boy with Green Hair" (1948). He also got to make films with his boyhood friend, Spencer Tracey, in "People Against O'Hara" (1951). In 1960, he starred in a short-lived television sitcom, "Harrigan and Son" (1960-1961), and guest-starred on numerous television shows. Politically, he was extremely right-wing conservative, and many of his fellow actors thought he was a near-fascist. He was married to the former Eloise Taylor, and they had four children (three of them adopted). His autobiography, "The Wind at my Back" was published in 1964. His last film was "Ragtime" (1981). He died in Santa Monica, California, from a heart attack.