The cause of death was cancer, her son, Matt Conlon, told The New York Times.
She was the voice of Faline, a doe in the Disney animated film, "Bambi" -- her only other acting credit.
"I peaked in show business at age 5," she was often quoted as saying.
Eleanore Cammack King was born Aug. 5, 1934, in Los Angeles. A graduate of the University of Southern California, she worked for the Mendocino Coast Chamber of Commerce, starting its film commission, the Times said.
Asked one time about her role in the popularity of "Gone With The Wind," she replied, "I had nothing to do with it. I was 5. They said, 'Stand here. Do this.'"
Besides her son Matt, she is survived by a daughter and three grandchildren. Her first husband, Ned Pollack, died in 1965. She married Michael Conlon in 1971 and they were divorced in 1976.