Nelson's maternal grandparents were football star Tom Harmon, a Heisman Trophy winner from the University of Michigan, and actress Elyse Knox.

[citation needed] At age four Nelson played one of Henry Fonda and Lucille Ball's daughters in Yours, Mine and Ours (1968).

[6] Nelson is a professional dancer, having studied ballet for 17 years with Tania Lachine and toured throughout California in a dance company while still in grammar school.

Nelson studied theater with Kim Stanley and Nina Foch and briefly in the United Kingdom, performing in The Edinburgh Fringe Festival after graduation from high school.

In 1982, she played "valley girl" Jennifer DeNuccio on the television series Square Pegs,[7]: 1007  and in 1986 she landed the role of the anorexic daughter in Paul Mazursky's film Down and Out in Beverly Hills.

Elsewhere, Murphy Brown, The Nanny, 7th Heaven, Melrose Place, Will and Grace, Matlock, Diagnosis Murder and Seinfeld.

Nelson went into remission after surgery, chemotherapy (ABVD) and radiation at Cedars-Sinai Hospital in Los Angeles.