Born as Joan Felt, she became an accomplished child actress, scoring personal successes on Broadway in the hit musical Panama Hattie, and the 1940 film, Primrose Path, asGinger Rogers's younger sister. Carroll became RKO Radio Pictures' resident juvenile personality in both "A" and "B" pictures. RKO starred Carroll in two zany comedy vehicles,Obliging Young Lady and Petticoat Larceny.

She continued to work in films as an adolescent, but less frequently. Two of her best-remembered pictures came from this period: Meet Me In St. Louis (1944) as Judy Garland andMargaret O'Brien's sister, and The Bells of St. Mary's (1945), in which she played a troubled teen daughter with an estranged father.

Currently residing in the American Southwest, Joan and her brother donated a historic family lamp to the Nevada State Museum on July 7, 2011. The lamp was originally given to her father, Wright Lafayette Felt, who was the Public Works Administrator for Nevada at the time the Hoover Dam was built. The lamp was created out of materials used in the construction of the 155-mile, $900,000 power line to the Hoover Dam, and was presented to him by the Lincoln County Power District No. 1 on Sept. 25, 1937, for his assistance with the project.

Source: Wikipedia