Rupp continued to devote herself to acting full-time through the 1980s and performed in numerous regional stage productions. One such production was Sherry Kramer's "Wall of Water" in New Haven, Connecticut, at the Yale Repertory Theatre's Winterfest play festival of 1988. She guest-starred on numerous television shows, including "Kate & Allie", "Spenser for Hire", and "The Days and Nights of Molly Dodd". In 1988, Rupp landed her first feature-film role as Miss Patterson, the timid secretary of Tom Hanks' Josh Baskin, in the comedy "Big".