After appearing on Broadway in the stage version of Tribute, she first rose to prominence as Dr. Faith Coleridge on the soap opera Ryan's Hope 1976 - 1978. In 1979, she co-starred in the television version of The Bad News Bears. But it was her Emmy-nominated portrayal of Marilyn Monroe in the 1980 TV movie Marilyn: The Untold Story that first established her. In 1982, she took the lead role in the comedy/detective series Tucker's Witch opposite Tim Matheson. Supporting roles in movies followed, with appearances in Star Trek IV: The Voyage Home as Dr. Gillian Taylor, Peggy Sue Got Married (both in 1986), and as the mother in the first horror film of the "Chucky" film series Child's Play (in 1988). The next year, she starred opposite Tony Danza in She's Out of Control.

In the first half of the 1990s, Hicks found work in TV movies, but it wasn't until 1996 when she was cast as Annie Camden on the syndicated family drama 7th Heaven (opposite fellow Star Trek alum Stephen Collins)