John Wayne, who was 41 when the film was made, won great acclaim for his portrayal of 60-year-old Capt. Nathan Brittles.
John Ford initially was uncertain who to cast in the lead role. However, he knew that he did not want John Wayne for the part, taking into account that, among other factors, Wayne would be playing a character over 20 years older than he was at the time. Reportedly, Wayne's performance in Red River (1948) changed Ford's mind, causing him to exclaim, "I didn't know the big son of a bitch could act!" Ford realized Wayne had grown considerably as an actor, and was now capable of playing the character he envisaged for this film. When shooting was completed, Ford presented Wayne with a cake with the message, "You're an actor now."
John Wayne felt his Academy Award nomination for Best Actor of 1949 should have been for this film instead of Sands of Iwo Jima (1949).
The exterior shots of Capt. Brittles' quarters is still standing at Gouldings Lodge, just outside of Monument Valley itself. The town of Kanab is 210 miles west of Monument Valley.