Maureen O'Sullivan was born Maureen Paula O’Sullivan in Boyle, County Roscommon, Ireland, in 1911. Her father was a military officer who served in World War I. She was schooled in a convent and one of her classmates was the future film actress Vivien Leigh. After attending finishing school in France, O'Sullivan returned to Ireland and began working with the poor.
Her film career began when she met director Frank Borzage, who was doing location filming in 1930 for Fox Film. She was given a part in his movie and then traveled to the United States to complete filming in Hollywood.
Her big break, however, came when MGM studio executive Irving Thalberg chose O'Sullivan to appear as Jane Parker in Tarzan the Ape Man (1932) opposite co-star Johnny Weissmuller. Although she appeared with Weissmuller in five subsequent sequels, O’Sullivan was also careful to branch out into other roles in order not to be typecast.
In 1942, O’Sullivan took a break from filming for several years to care for her husband after he contracted typhoid while serving in the Navy.
Beginning in the 1950s, O’Sullivan primarily appeared in television roles.
After a career spanning 65 feature films, her last picture was released in 1988.
O’Sullivan married writer and Oscar-winning director John Farrow in 1936. They raised seven children, including actresses Mia Farrow, Stephanie Farrow and Tisa Farrow. Her eldest son died while taking flying lessons in 1958. Her husband passed away in 1963. O’Sullivan married James Cushing in 1983.
She died from complications after heart surgery in Scottsdale, Arizona in 1998. She was 87 years old.