Hardin started her acting career as the young star of the television series Thunder (1977–1978), and has appeared in over 70 movies and television programs since, including two 1981 Little House on the Prairie episodes (as Belinda Stevens in "The Reincarnation of Nellie", Parts 1 and 2) as well as playing Michele Pierson in the 1983 television movie Little House: Look Back to Yesterday. She starred as Baby in the short-lived 1988 television series Dirty Dancing (based on the 1987 film of the same name) and two 1992 episodes of Quantum Leap (as Abigail in "Trilogy," Parts 2 and 3). She co-starred in the 1990 dance movie Lambada as Sandy. She appeared in Absolute Power (1997) as Christy Sullivan and played Ross's dirty-talking love interest in the season 1 Friends episode "The One with the Stoned Guy". She was also originally cast in Back to the Future as Jennifer Parker, but was re-cast after Eric Stoltz (the original Marty McFly) was let go. Upon Michael J. Fox being cast, Hardin was deemed too tall to star alongside him. She was later replaced by Claudia Wells.