Evelyn Keyes, one of the last surviving co-stars of “Gone With the Wind” and a popular film actress in the 1940s, died July 4 at an assisted-living home in Montecito, Calif. She was 91.

Keyes died of cancer, said the producer Allan Glaser, a friend, who told The Associated Press that the announcement had been delayed until the death certificate was filed.

Keyes played the pouty Suellen O’Hara, whose sister Scarlett steals her longtime boyfriend and marries him just to pay the taxes on the plantation, in the Academy Award-winning 1939 movie classic. But, in later years, she became almost as well known for her first memoir, “Scarlett O’Hara’s Younger Sister,” as for any of her movie roles. The book, published in 1977, concentrated on her numerous marriages and love affairs with the mostly rich and famous.

She was quoted as saying, “I always took up with the man of the moment, and there were many such moments.”

Her first husband (1938-40) was Barton Bainbridge, a businessman. After she left him, for the Budapest-born director Charles Vidor, he committed suicide. She and Vidor married in 1944 but divorced the next year. Her third husband was John Huston, the director, writer, producer and actor.

After her 1950 divorce from Huston, Keyes was the constant companion of the producer Mike Todd. He left her for Elizabeth Taylor in 1956. The next year Keyes married the bandleader Artie Shaw (whose ex-wives included Ava Gardner and Lana Turner). They separated in the 1970s but did not divorce until 1985. After his death in 2004, she sued his estate and was awarded $1.42 million.