He is best known for his role as a lonely little boy who befriends a pack of killer rats in the film Ben (1972), as Karen Black's son Davey in the cult classic Burnt Offerings, and as Sarah Jessica Parker's hunky dance partner, Jeff Malene, in Girls Just Want to Have Fun (1985).
He made his debut in the Disney film The Million Dollar Duck in 1971, before landing a starring role in Ben (1972), the sequel to Willard (1971).
He made appearances on television series such as The Mod Squad; Columbo; The Streets of San Francisco; Kojak; Adam-12; Emergency!
He also played Jeff Malene in the teen comedy Girls Just Want to Have Fun (1985), where he engages in a notable dance scene with co-star Sarah Jessica Parker.
Montgomery resurfaced around 2012, appearing at Monster-Mania Con 25 in 2016[3] and other horror-themed conventions, signing photos and posing for pictures with fans.