Slater's early stage and television work led to his 1985 big-screen debut in The Ballad of Billie Jean, followed by a role opposite Sean Connery in The Name of the Rose (1986). In 1989, Slater gained star status with his memorably maniacal turn in the cult favorite Heathers. The next decade proved demanding as Slater appeared in Pump Up the Volume (1990), Robin Hood: Prince of Thieves (1991), Interview with the Vampire (1994) and the high-octane Broken Arrow (1996).
Slater returned to the stage in 2004 in a London production of "One Flew Over the Cuckoo's Nest." His later film roles include Mindhunters (2004) and Alone in the Dark (2005).