All of Bob Newhart’s cameos on the Big Bang Theory, ranked

Bob Newhart was an actor and standup comedian who featured in many iconic shows and films before his demise on July 18, 2024. One of his most iconic roles was on the science-comedy The Big Bang Theory, created by Chuck Lorre and Bill Prady.

Newhart played the character of Arthur Jeffries, also known as Professor Proton, on the sitcom. Professor Proton was a scientist who turned to acting and hosted a science experiment show for kids. The Big Bang Theory protagonist, Sheldon Cooper, grew up watching Professor Proton and considered him an idol.

Bob Newhart appeared in six episodes in the 12 seasons of the show. Here are all his cameos, ranked as per the author's preference. (Note: this is not a comment on the show or episode, just a ranking as per the writer's opinion)

Disclaimer: This article contains spoilers for The Big Bang Theory.

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All cameos with Bob Newhart as Professor Proton on The Big Bang Theory ranked

1) The Proton Transmogrification - Season 7 episode 22

Bob Newhart as Arthur Jeffries in a dream sequence in The Big Bang Theory (Image via Netflix)

In this episode, Sheldon Cooper (Jim Parsons) receives the news that his idol and the man behind Professor Proton, Arthur Jeffries, has passed away. Sheldon refuses to attend his funeral and has a rough day as he tries to process the loss.

However, Bob Newhart features in this episode as a spectral vision of his human self in Sheldon's dream. Sheldon even compares him to Obi-Wan Kenobi, who became a spirit mentor to the Star Wars protagonist Luke Skywalker.

Arthur talks to Sheldon about his feelings after hearing of the loss. Sheldon mentions that he also lost his grandfather and father, George, stating that all the men he looks up to eventually pass on. Arthur consoles Sheldon, teaching him that it is all right to grieve the losses in life.

Arthur Jeffries then explains that it is important to cherish the people who care for you and let them know about it. This advice helps Sheldon appreciate Leonard and get over Arthur's death. At the end of the episode, Arthur appears in Sheldon's vision again, saying he might appear in dreams whenever Sheldon needs him most.

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2) The Opening Night Excitation - Season 9 episode 11

Bob Newhart as Arthur Jeffries in a dream scene from The Big Bang Theory (Image via Netflix)

Sheldon is all set to watch the new Star Wars movie when Penny reminds him that his girlfriend Amy's birthday is on the same day as the film's release. Conflicted, Sheldon dreams of Professor Proton/Arthur Jeffries. We find out Arthur has been in Sheldon's dreams before to offer him advice or even to act as a night light at times.

Arthur tells Sheldon he should spend the day with Amy and be there for her. Sheldon decides to do so and gives his ticket away, deciding to watch the movie later. At the end of the episode, Arthur even reappears in Sheldon's dream to ask for a follow-up about how Amy's birthday went.

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3) The Proton Displacement - Season 7 episode 7

Bob Newhart with Kaley Cuoco in a scene from The Big Bang Theory (Image via Netflix)

Leonard, Sheldon, and Amy meet Bob Newhart's character, Arthur Jeffries, at a pharmacy. After this, he asks Leonard to help him with a physics paper on nano vacuum tubes, which annoys Sheldon immensely.

Sheldon tries to make many efforts to have his idol work on the paper with him, including going to his house in the middle of the night. He even recruits Bill Nye the Science Guy to make Arthur jealous. Finally, Arthur feels bad for Sheldon and asks him to collaborate on the paper, joining the gang for a cup of tea with Penny (Kaley Cuoco) in the apartment.

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4) The Proton Resurgence - Season 6 episode 22

Bob Newhart as Professor Proton, hugging Jim Parsons as Sheldon Cooper on The Big Bang Theory (Image via Netflix)

This episode marks the first time Bob Newhart made an appearance as Arthur Jeffries, aka Professor Proton, on The Big Bang Theory. Sheldon finds him online and calls the older scientist to his and Leonard's apartment. Under the impression that there are kids who want to see Professor Proton live, Arthur reaches their home.

In a hilarious sequence that follows, Penny, Sheldon, and Leonard watch in raptures as Arthur performs kiddie science experiments in their living room. However, he feels that he doesn't want to be Professor Proton anymore after thinking that he brings no worth to the scientific world. Sheldon tells Arthur how he is an inspiration to thousands of young children who take up science, and those inventions are because Arthur sparked their interest.

At the end of the episode, the audience sees Arthur and Sheldon forming a bond, eager on Sheldon's end and a bit grudging on Arthur's.

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5) The Proton Regeneration - Season 11 episode 6

Bob Newhart and Jim Parsons as Arthur Jeffries and Sheldon Cooper on The Big Bang Theory (Image via Netflix)

The makers of the Professor Proton show decide to reboot the series and Sheldon is sceptical about who they might cast in the role. He even auditions and petitions for himself to lead the show but is unconvincing with his acting. Sheldon goes to his friend Wil Wheaton for acting tips.

However, the story encounters a twist when Wil auditions for the role and even gets cast as Professor Proton. Annoyed at this development, Sheldon dreams of Arthur Jeffries, the original Professor Proton. The two have a conversation in a swamp, but Sheldon remains angry at Wil even at the end.

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6) The Planetarium Collision - Season 12 episode 5

Bob Newhart as Arthur Jeffries in a dream sequence on The Big Bang Theory (Image via Netflix)

This episode is the shortest cameo that Bob Newhart makes on the show. Sheldon and Amy (Mayim Bialik) have a bad quarrel over Amy not finding the time to collaborate on a super asymmetry project. Sheldon tries to help by asking the president of their research university to free her work up, but she ends up being removed from her own project.

After this, Amy is rightfully upset with Sheldon. That night, Sheldon dreams of Professor Proton sitting in a diner. He tells Sheldon to sort out his issue with Amy. Here, Sheldon acknowledges that the spirit is just a manifestation of his subconscious. After waking up, Sheldon and Amy have a mature conversation about their insecurities and their respective projects and thresh out their fight.

This episode marks the last cameo from Bob Newhart's Arthur Jeffries on The Big Bang Theory.

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Bob Newhart was an actor and standup comedian who featured in many sitcoms and comedy specials in his career. He was known for his deadpan comedy, which he delivered with a hesitant stutter that became a trademark of his style.

Bob Newhart passed away on July 18, 2024, at 94. His publicist released a statement to the press, stating that Newhart had suffered a series of illnesses recently. He was married to Ginny Newhart and is survived by his four children, Robert, Jennifer, Courtney, and Timothy.