Bill Quinn, the actor who played the recurring role of the mailman for Bob Hartley's office building, was Newhart's father-in-law in real life.
Actor Peter Bonerz who played Jerry the dentist learned how to direct on the set of this show and went on to become an award-winning director of other comedy series.
Suzanne Pleshette was cast after she appeared on The Tonight Show Starring Johnny Carson (1962), seated by happenstance next to Bob Newhart. Producers thought she and Bob clicked together and asked her to read for the show.
When Bob Newhart read the premise for the proposed series, he insisted on two changes. First, he insisted that his character be changed from a psychiatrist to a psychologist so he wouldn't make fun of the seriously mentally ill, and he insisted that his character have no children as to avoid the standard scenario of a goofy father.
The characters Bob Hartley and Carol Kester-Bondurant appeared outside The Bob Newhart Show (1972) in the 1994 episode of Murphy Brown (1988) when Carol became Murphy's 66th secretary. Unlike all of Murphy's other secretaries, Carol (Marcia Wallace) is a great secretary. Unfortunately (for Murphy), Bob Newhart (as Bob Hartley) shows up at the end of the show to convinces her to come back to work for him.