Fortunately, her business school training turned out to be unnecessary when a London studio asked her to film a screen test. Though the test was initially dismissed by studio heads, famed British actor Charles Laughton saw something in it and encouraged the studio to sign Maureen. She was soon signed to a seven year contract, with her first screen appearance starring opposite Laughton in Alfred Hitchcock's Jamaica Inn (1938). Laughton was so impressed by Maureen that they co-starred in a second picture, The Hunchback of Notre Dame in 1939, which was filmed in Hollywood. This and the outbreak of the second world war was the turning point in bringing and keeping her in the United States.
Because it was unsafe to shoot films in London, Maureen's London contract was sold to RKO studios soon after shooting on the Hunchback was completed. She spent her first few years in Hollywood starring in low budget films and would have kept doing so had she not caught the attention of director John Ford, who cast her in his Academy Award winning film, How Green Was My Valley (1941). She would go on to partner with John Ford and one of his favourite actors John Wayne in Rio Grande (1950), The Quiet Man (1952), and The Wings of Eagles (1957). Her chemistry with Wayne offscreen was indicative of the easy friendship between the two in real life. While her work with Ford and Wayne were important milestones for Maureen, her two most recognizable roles playing firry independent mothers in family favourites Miracle on 34th Street (1947) and The Parent Trap (1961).
Though best known for her acting, Ms. O'Hara has often said that singing is her first love, a talent she displayed in film and television appearances during the late fifties and sixties. She has released two albums of music.
She married three times, her third husband transatlantic aviator Charles F. Blair Jr. passing away in an air accident in 1978. Though she retired a few years after her 1968 marriage to Blair, she made a small comeback in 1991's Only The Lonely, starring as John Candy's domineering mother. She went on to make several small appearances in made-for-tv movies during the nineties. She has since slowed down her acting again and now splits her time between homes in Arizona, The Virgin Islands, and Cork Ireland.

