Bob Newhart’s guest role on The Big Bang Theory became one of the sitcom’s most beloved highlights — and earned the comedy legend his first-ever Emmy. But his participation came with two non-negotiable conditions that ultimately shaped Professor Proton’s legacy.
Before agreeing to join the CBS hit, Newhart insisted that his character appear in more than one episode and that all scenes be filmed in front of a live studio audience. For Newhart, live laughter wasn’t optional — it was essential. “That’s the only way I function,” he famously said, explaining that real-time audience reactions give performances energy no laugh track can replace.
Producers agreed, expanding what was meant to be a one-off appearance into a semi-recurring role. Newhart went on to appear six times as Professor Proton, the childhood TV hero who inspired Sheldon and Leonard.