Margaret Brooke Sullavan came from an old, wealthy family from Virginia. She attended the best private schools and began the theatricals at Harvard University. Later, she played with a student theater group in Massachusetts, which also included James Stewart and Henry Fonda. On Broadway, she debuted in 1931 and later returned again and again to the stages of Broadway.

She finished 1933 a contract with Universal and was already starting with their first role in the strip Only Yesterday the biggest star of the studio. The following roles were not artistically undemanding and the actress left in 1936, studio that could be saved in the same year, with Deanna Durbin in financial ruin.

From 1938, the actress turned under a contract with MGM, where she delivered at the side of Robert Taylor in 1938 in Three Comrades one of their finest performances. In the same year she appeared in alongside Joan Crawford in the burning fire of passion. A broad public, the actress was not known until she appeared alongside Charles Boyer in the remake of Back Street.

She never made it permanently, get her turbulent personal life under control. In 1931 she married Henry Fonda. However, the marriage lasted only two months. Of short duration was also her second marriage to director William Wyler, which lasted from 1934 to 1936. Slightly longer, but no less difficult was it living with her third husband, the theater and film agent Leland Hayward from 1936 to 1947. The couple had three children. The children are traumatized by the marriage, and daughter Bridget later committed suicide. She was a friend of Peter Fonda, the son of the first husband of her mother, who later named his daughter Bridget Fonda for her. Daughter, Brooke Hayward wrote on under the title of Haywire, the family history. In the television adaptation of 1980 Lee Remick played the role of Margaret Sullavan.

Margaret Sullavan, was found unconscious at the age of 50 years in the New Year's Eve of 1960 in a hotel in New Haven, Connecticut. Unconsciousness moved her from an overdose of barbiturates, which also led to her early death. It is natural to suspect a suicide with observed sleeping pills too, as the official cause of death was found but an accident.