Foster has done multiple stints as Bloom on Broadway. Foster received a Tony nomination for his work as Seymour Krelbourn in Little Shop of Horrors. He originated the role of Bobby Strong in the Broadway and off-Broadway companies of Urinetown for which he earned Outer Critic Circle and Lortel Award nominations. His other Broadway credits include Grease, Footloose and Les Misérables. Foster also notably toured nationally in Cats, was a member of the Martin Guerre company, appeared in Children of Eden at Paper Mill Playhouse, starred in Mister Roberts at the Kennedy Center and starred off-Broadway in Modern Orthodox.