Bob Newhart as Arthur Jeffries — Then
The host of the children’s science program “Professor Proton” was Arthur Jeffries. He was a role model for Sheldon and Leonard when they were young, and to their joy, they subsequently got to know him in person.
Jeffries passes away in season seven, but it doesn’t mean he was taken off the program. He continued to show up in Sheldon’s dreams for a few more times, frequently appearing slightly off-balance and dressed in a “Star Wars” outfit.
Bob Newhart as Arthur Jeffries — Now
Although Bib Newhart doesn’t require an introduction, we’ll do it anyhow. Newhart has been a legend for many years because to his masterful use of deadpan humor. His record of humorous monologues, “The Button-Down Mind Of Bob Newhart,” gave him his big break in 1960, and he went on to have one of the most successful careers in comedy history.
After his appearance in “The Big Bang Theory,” Newhart continued to play Professor Proton in the prequel series “Young Sheldon,” which portrayed Sheldon’s childhood. This time, though, it was largely in the voice-over capacity.
Brian Posehn as Bert Kibbler — Then
Another Caltech researcher named Bert is a geologist who, as is required by his line of work, appreciates the odd rock pun. In season 7, Bert shows some interest in Amy, but she is unaware of it until her friends inform her.
But we wouldn’t be concerned about Bert’s future. He subsequently proves to be a really kind person with a great career, and he even receives a posh research grant, something the rest of the gang can only wish for.
Brian Posehn as Bert Kibbler — Now
Brian Posehn has a ton of acting credentials, while mostly playing little roles. In the middle of the 1990s, he made his acting debut in a number of minor roles, and he has been active ever since. He has worked in movies, television, voice acting, and even television production and writing.
A recurrent part in the TV series “Top Secret Videos” and the voice role of Sour Cream in the sophisticated animation “Steven Universe” are among his most recent roles.
Judd Hirsch as Alfred Hofstadter — Then
Even though Leonard Hofstadter’s father is frequently referenced throughout the series, he only physically appears in a maximum of two episodes. Before that, all the information viewers had about him came from Beverly, Leonard’s mother, and didn’t create a very favorable picture of him.
However, their ultimate divorce serves both of them well. In reality, he meets Mary, Sheldon’s mother, near the conclusion of season 9, and the two appear to get along well, which raises the possibility of an intriguing romance.
Judd Hirsch as Alfred Hofstadter — Now
The amazing acting career of Judd Hirsch dates all the way back to the first decade of the 1970s! He began with a few little, uncredited appearances before progressively moving up the ranks and landing his most enduring role as Alex Reiger in the long-running television series “Taxi.”
The actor’s performance in TBBT was but a drop in the ocean of roles he has played. He continued to feature regularly in other TV shows after the program had finished and even provided the voice for the popular adult animation “Big Mouth” on Netflix.
Regina King as Janine Davis — Then
It’s wonderful to periodically be reminded of a regular person’s perspective in a program when the most of the characters are uncomfortable and socially awkward. Although she works at Caltech, Janine Davis is not a scientist. She is one of the very few rational voices on the broadcast since she works for the university’s human resources office.
You can count on Janine to set the rules and impart some fundamental manners if one of the core gang’s men inadvertently behaves inappropriately. We value her assistance very highly.
Regina King as Janine Davis — Now
You are compelled to respect Regina King because of her regal name. When she was cast as Brenda Jenkin in “227,” her acting career got off to a fast start. She played Brenda Jenkin for five years and 110 episodes. Not bad for a debut concert!
Since then, we’ve lost track of how many programs this amazing actress has been in as a series regular. “Southland,” “American Crime,” and “24” are just a few examples.) Following the conclusion of TBBT, King went on to feature as Sister Night (also known as Angela Abar) in the popular superhero movie “Watchmen.”
Joshua Malina as President Siebert — Then
Everyone stand up! Oh, he’s not that president, I see. The head of Caltech and a physicist is Dr. Siebert. He mostly worries about money, money, and more money.
He first appears in season 3, and throughout the remaining seasons of the show, his performances are sprinkled throughout. But in the 12th and final season, we see a lot more of him, largely because Sheldon’s research is advancing and he is in contention for the Nobel Prize.
Joshua Malina as President Siebert — Now
Prior to landing his first significant role as Jeremy Goodwin in “Sports Night,” Molina had been acting since the early 1990s, primarily in supporting parts. He worked on that for two years before moving on to other endeavors, such as becoming a regular cast member of “The West Wing” and “Scandal.”
Malina only received modest TV appearances after TBBT, but we’re sure to see him in a significant role very soon.
