Barber's first major role was as the original Carrie Brady on the American soap opera Days of our Lives, from 1982 to 1986. She also guest starred and starred in many movies and television series. Barber is known for her role on the TV show Full House as Kimmy Gibbler, the best friend of D.J. Tanner (Candace Cameron Bure), the oldest daughter in the Tanner household, which she played from 1987 to present. She was at first a recurring role but shortly thereafter became a regular. After Full House ended, Barber retired from acting and started focusing on her personal life. In 2012, Barber reprised the role for a Funny or Die sketch alongside Dave Coulier, her former Full House co-star, and says she would love to return to acting.
Barber is the youngest of Donald and Sherry Barber's three children; she has two older brothers, Darin and Justin. Barber married Jeremy Rytky on September 1, 2002. The couple have two children: son Tate James Rytky (born April 30, 2004) and daughter Felicity Ruth Rytky (born April 10, 2007). She graduated from La Serna High School in Whittier, California, and earned a degree in English from Whittier College. Barber also has a MA in Women's Studies from the University of York, England. She returned to Whittier as assistant to the director of Whittier College's Office of International Programs.