Chadman made his Broadway debut in 1968, as an ensemble dancer in Darling of the Day (with Vincent Price). More chorus dance parts followed, and then in 1972, he was cast by noted choreographer/director Bob Fosse in Pippin. Chadman originated the role of Lewis (opposite Ben Vereen) and reprised it for a 1981 television version. He worked with Fosse again in Chicago (originating Fred Casely), played Rosencrantz in the short-lived rock musical Rockabye Hamlet, and starred in the 1976 revival of Pal Joey.