Robertson started taking acting classes when she was ten, and had roles in local theater productions. Her first television guest appearances were in My Secret Identity and E.N.G.. She then appeared in Maniac Mansion from 1990–1993, playing Tina Edison, the eldest of three children of Dr. Fred Edison (Joe Flaherty). She did not debut on the big screen until her small role in the Brenton Spencer film Blown Away.
In 1994 Robertson was cast as Clare Arnold in Fox series Beverly Hills, 90210, and play