Ruehl debuted on film in The Warriors (1979) and continued to find steady employment in such movies as Four Friends (1981) and Heartburn (1986). In 1988, she appeared in the box-office smash Big and gained notoriety as a mafioso's hellcat wife in Married to the Mob (1988). Playing opposite Jeff Bridges in The Fisher King (1991), Ruehl collected a richly deserved Oscar and a Golden Globe for her potent supporting turn.
For the rest of the '90s, Ruehl alternated between feature films and television. Her big-screen works included Last Action Hero (1993) and The Minus Man (1999), and her TV credits included the made-for-cable film Gia (1998).