Bob Newhart is the son of George David Newhart and Julia Pauline Newhart. His mother was a housewife and his father was a part owner of a plumbing and heating-supply business. His mother was of German and Irish descent.

The name Newhart is German. One of his grandmothers was from St. Catherines, Ontario, Canada.

Newhart rose to fame in 1960 when his album of comedic monologues, The Button-Down reached number one on the Billboard pop album chart; it remains the 20th-best-selling comedy album in history.

The follow-up album, The Button Mind Strikes Back!, was also a success, and the two albums held the Billboard number one and number two spots simultaneously.

In 2013, Newhart made the first of his six guest appearances on The Big Bang Theory as Professor Proton, for which he received the first Primetime Emmy Awards.