By the time that she was 5, Tracy had a film credit to her name. The daughter of singer Ricky Nelson and Kris Harmon, she appeared as one of Henry Fonda's daughters in the movie 'Yours, Mine and Ours (1968)'. In 1982, she became the popular valley girl Jennifer DeNuccio on the Television series "Square Pegs" which ran from 1982-83. This popular show would make Tracy's name well known. She would make a few small appearances in movies, but she would pursue Television and return in the 1984 series "Glitter". Two years later, she was in the Nick Nolte movie 'Down and Out in Beverly Hills (1986)'. In 1987, Tracy was very sick and was diagnosed with Hodgkin's disease. In 1989, she returned to Television as Sister Stephanie Oscalsky, nosey detective, in "Father Dowling Mysteries". Since that time, she has appeared in a handful of Television Movies and had a reoccurring role on "Melrose Place" and "A League of Their Own (1993)".