His first network television appearance was in 1965 on The Addams Family in the season-two episode "Morticia, The Writer". He had several more TV appearances in the late 1960s and also had roles in several films, including Medium Cool (1969) and Catch-22 (1970), the latter of which also included his future co-star Bob Newhart. In 1971, Bonerz was part of an ensemble cast in the short-lived improvisational television show Story Theatre, which also included Alan Alda and Valerie Harper. In 1972, he landed the popular supporting role of Dr. Jerry Robinson, the eccentric orthodontist on The Bob Newhart Show, whose most frequent comic foil was Marcia Wallace as Carol, the sharp-tongued receptionist. He also directed 29 episodes. The show ran for six seasons, with ratings among the top 20 in the first three seasons.