Born to Charles FitzSimons (a Catholic) and Marguerita Lilburn (a Protestant) in Ranelagh, County Dublin, Ireland not long before partition, the famously red-headed beauty is noted for playing fiercely passionate heroines with a highly sensible attitude. She often worked with director John Ford and longtime friend John Wayne.

She came from a theatrical family and began acting at the age of 14 with the Abbey Theatre in Dublin (Ireland's National Theatre). At the age of 17, after a brief marriage (which was later annulled) to the man who would become the father of British journalist Tina Brown, she was offered a screen test in London. Initially reluctant, she was persuaded to attend. Famed actor Charles Laughton attended the screen test. She performed poorly in the test and returned to Ireland. However, Charles Laughton believed she had "something." Laughton looked at the test again and, while he thought it was awful, he couldn't forget her eyes. He told his business partner he was signing her and sent him the test tape. When he saw the tape, the partner was furious as he believed it was a poor choice. However, he came around when he too found he couldn't forget her eyes. As a result she was offered an initial seven year contract. Her first major film was to be Alfred Hitchcock's Jamaica Inn.

In 1939, she and Laughton went to the U.S. to appear in The Hunchback of Notre Dame. This film contains one of her most famous roles, playing Esmeralda alongside Laughton's Quasimodo.

Her mother was a trained opera singer and she herself aspired to a singing career. She sang briefly in How Green Was My Valley and again in The Quiet Man. She starred on Broadway in the musical Christine and released two successful recordings, "Love Letter from Maureen O'Hara" and "Maureen O'Hara Sings her Favorite Irish Songs". During the 1960s she was a sought after guest on musical variety shows appearing with Perry Como, Andy Williams, Betty Grable and Ernie Ford. She is a fluent Irish speaker and used this in her films The Long Gray Line, The Quiet Man and most recently in Only the Lonely.

She is one of the most beloved of Hollywood's Golden Age icons, in the company of such screen luminaries as Marilyn Monroe, Judy Garland, and Elizabeth Taylor. Many of her films are considered all-time classics and are traditionally shown on television during the holidays. Once named one of the world's most beautiful women, O'Hara's beautiful face and thick red hair blowing in the wind as she waves from a gate in the John Ford Academy Award winning film How Green Was My Valley will remain one of the most iconic images ever preserved on film.

Maureen married Charles Blair in 1968. Blair was a pioneer of transatlatic aviation, a former Brigadier General of the US Air Force and a former Chief Pilot at Pan Am. A few years after her marriage to Blair, O'Hara for the most part retired from acting. According to O'Hara, one day she was with Blair and John Wayne when she was asked if she didn't think it was time for her to stop working and stay at home. Instead of the getting into an argument that O'Hara thought Blair and Wayne were expecting, she agreed that it was time to stop working. Blair later died in 1978 when the engine of a Grumman Goose he was flying from St Croix to St Thomas exploded.

O'Hara remained retired from acting until 1991, when she starred in the movie Only the Lonely. In this role she played Rose Muldoon, the mother of Danny Muldoon, who was played by John Candy.

For her contributions to the motion picture industry, Maureen O'Hara has a star on the Hollywood Walk of Fame at 7004 Hollywood Blvd. In 1993, she was inducted into the Western Performers Hall of Fame at the National Cowboy & Western Heritage Museum in Oklahoma City, Oklahoma. In March 1999 Maureen was selected to be the Grand Marshal of the New York City St. Patrick's Day Parade after previously being de-selected because she was a divorceé.

In 2004 Maureen O'Hara released her autobiography Tis Herself, published by Simon & Schuster. In the same year she was also honored with the Lifetime Achievement Award by the Irish Film and Television Academy in her native Dublin, Ireland.