George O'Brien was the son of the San Francisco Chief of Police, and he went on to become a renowned college athlete. During World War I, he held the esteemed title of Heavyweight Boxing Champion of the Pacific Fleet.
Following the war, George made his way to Hollywood, where he worked as a stuntman and part-time actor in the early 1920s. It was in 1924 that Director John Ford discovered him and cast him in his first film, The Iron Horse. Over the next two years, George appeared in four more Ford films, including The Blue Eagle and Sunrise, in which he co-starred with Janet Gaynor.
Sunrise, a film that won two Academy Awards, told the story of a simple farmer who is swayed by another woman to murder his wife. George's popularity endured until the advent of sound in film, at which point his popularity began to wane. Nevertheless, he made the transition to sound and leveraged his rugged looks and physical size to become a Western Cowboy Star.
Throughout the 1930s, George appeared in some of the best and worst stories ever written, including Riders of the Purple Sage. He was consistently among the top ten money-making Western Stars, and although he occasionally took on roles outside the Western genre, such as in Ever Since Eve, these appearances were few and far between.
By the end of the 1930s, George had become a popular 'B' movie Cowboy Star, but he did not take his roles as seriously as he once had. During World War II, he hung up his acting boots and re-enlisted in the Navy, where he fought in the Pacific and was decorated numerous times.
After the war, when he found it difficult to secure acting work, John Ford, his old director, offered him a role with the cavalry in three of his films.