Carson was born in Brooklyn, New York; her father is a journalism professor at the University of Florida, and her mother was a kindergarten teacher in New York. She spent her adolescence in Gainesville, Florida and attended F. W. Buchholz High School. Her parents separated when she was 14, and her mother moved back to New York alone. In 1986, she entered the Regional competition sponsored by the "America's Junior Miss" talent show, taking second place for the region held in Gainesville. After graduating in 1987, Carson returned to New York and decided that she wanted to be an actor. She began her career by appearing in a number of After School Specials and HBO short films.