Kelly appeared in her first film, Fourteen Hours[?] (1951), when she was 22. The following year she starred in High Noon (1952), a generally praised but somewhat controversial western starring Gary Cooper.
The film Mogambo, a drama set in the Kenyan jungle (1953), centers on the love triangle portrayed by Kelly, Clark Gable, and Ava Gardner and won Kelly an Oscar for best supporting actress. Kelly made three films with Alfred Hitchcock: Dial M for Murder, Rear Window, and To Catch a Thief.
In 1955 she was awarded the Academy Award for Best Actress for The Country Girl (1954). While it was being filmed she had engaged in a brief affair with its star Bing Crosby that was kept quiet to protect both their reputations.
Her being Catholic and able to bear children were key factors in her being chosen to marry Prince Rainier, as dynasties always make great import of their survival. Tales were circulated that because Monaco was established as a principality under the Salic Law it would revert to France if ever there was no male heir... and, though there is no requirement for a Catholic marriage, it was thought unlikely that a Catholic prince would divorce and remarry if his chosen wife was barren. In fact, there was really little actual danger that Monaco would revert to France as, since 1882, a childless prince of Monaco has been able to adopt an unrelated heir, thereby ensuring Monaco's survival as a principality. Nonetheless, survival of the nation was a different matter than the survival of the dynasty, and here there was a history of concern about fertility. Before Grace Kelly came on the scene, there was French film star Gisele Pascal, who was Rainier's mistress for six years (she was born Gisèle Tallone in Cannes[?]). Gisele and Rainier supposedly parted when a physical examination "found" her infertile (she later married and had children).
Prince Rainier and Princess Grace had three children:
In 2002, a new treaty between France and Monaco clarifies that if there are no heirs to carry on the dynasty, the Principality will remain an indepedent nation rather than revert to France.
At the age of 52, Princess Grace suffered a stroke while driving on the same stretch of highway in Monaco that had figured in To Catch a Thief. It resulted in an accident, and she died the next day without regaining consciousness. Princess Stephanie, who was alleged in some sources to have been the actual driver of the car, suffered only minor injuries.