An obituary published by her family in The Los Angeles Times confirmed that Leslie passed away in Los Angeles on Monday (October 12).
Leslie got her career breakthrough at the age of 15 as a disabled young woman in the Humphrey Bogart thriller High Sierra.
While still in her teenage years, Leslie racked up roles in the Oscar-winning Sergeant York, Yankee Doodle Dandy, This Is the Army and The Sky's the Limit.
In her later years, Leslie worked on television and made memorable appearances in Charlie's Angels, The Incredible Hulk and Murder, She Wrote, among other shows.
Leslie got married in 1950 to obstetrician Dr William Caldwell, with whom she had twin daughters. Dr Caldwell died back in 2000.
Watch a trailer for Yankee Doodle Dandy below: