Born in Coatesville, Pennsylvania, Richardson first started acting in plays in high school.
Initially, Richardson played bit roles in feature films American Graffiti (1973) and A Star Is Born (1976), and she guest-starred on the television series Happy Days and The Streets of San Francisco.
Shortly before her 25th birthday, about six years after moving to the West Coast, Richardson was picked to play the fourth-oldest child in the Bradford family on Eight Is Enough.
In her Eight Is Enough heyday, Richardson appeared in two installments of Battle of the Network Stars (May 1979 and December 1980), as well as numerous appearances on The $20,000 Pyramid, Password Plus, and Match Game, in addition to a one-hour All-Star episode of Family Feud in 1978 and a three-episode celebrity tournament on the daytime version in May 1979.
She reported she had experienced extremely hard times, living in an unheated trailer with a rotting floor in Wagontown, Pennsylvania, not far from her hometown of Coatesville.