In 1982, Cassidy had her first major feature film role as the replicant snake performer Zhora Salome in Ridley Scott's "Blade Runner". The following year, she co-starred in "Under Fire" with Gene Hackman and Nick Nolte. She continued to appear in both films and television; she co-starred in the television miniseries "Hollywood Wives" (1985), and appeared in "The Fourth Protocol" (1987), "Who Framed Roger Rabbit" (1988), "1969", "The Package" (1989), "Where the Heart Is" (1990) and "Don't Tell Mom the Babysitter's Dead" (1991). In 1993, she co-starred with Dudley Moore on the sitcom "Dudley", but the series only lasted for six episodes. She played the ex-wife of James Garner's lead character in the television movie, "The Rockford Files: I Still Love L.A." (1994).