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Principal Thomas Petersen, usually known as Principal Petersen is the principal of Medford High School. He is portrayed by Rex Linn.


Season 1[]

Principal Petersen is introduced in the series when he receives a complaint from three teachers about Sheldon Cooper, who is too smart. (Pilot (Young Sheldon))

He invites George and Mary into his office to discuss the option of sending him to a private school that is geared toward gifted students. He provides them information about Wilmot Academy, and informs the faculty about the choice. At 11am, he goes into the faculty lounge and sees three faculty members drinking alcohol in celebration. (An Eagle Feather, a String Bean, and an Eskimo)

Sheldon came to his office because a teacher sneezed. He decides to give him a few days of detention and told his parents. (A Sneeze, Detention, and Sissy Spacek)

Later in the school year, his secretary alerts him that Sheldon comes to his office while Givens sent him. Sheldon locks the door in the room with a chair, and he hears Sheldon using the announcement system, and gets to the secretary office by climbing in and out of a window. (Killer Asteroids, Oklahoma, and a Frizzy Hair Machine)

Principal Peterson is aware of the Communist comments made by Sheldon and that the community has communist hysteria and do not want any association. After the talk, he decides to do nothing until he receives another complaint. (A Loaf of Bread and a Grand Old Flag)

Principal Petersen had to summon Sheldon’s parents again to his office, and told him about the detention and the disrespect. He was not please with doing that act. While Sheldon sat outside his office, his secretary Janice sneezed, making him flee in a panic. (A Sneeze, Detention, and Sissy Spacek)

Petersen is at his office when his secretary Diana comes in with the news that Sheldon is back. He doesn’t want to deal with it and thinks Givens should man up. Sheldon gets on the intercom and he climbs through a window to stop him. (Killer Asteroids, Oklahoma, and a Frizzy Hair Machine)

Season 2[]

George came to his office and reveals that his wife Mary is pregnant; He already knew due to small town gossip. To deal with it, he gives a pay raise of $100/week. (Albert Einstein and the Story of Another Mary)

Unlike other teachers, he understands Sheldon Cooper and seems to like him. He also realizes that Sheldon has the highest aptitude test score, and that gives funding for the school. (A Perfect Score and a Bunsen Burner Marshmallow).

Later in the school year, he receives a letter from Sheldon stating that the laboratories are in poor condition, a situation he did not take seriously. He later witnesses Sheldon win the class President election and steps in to complete Sheldon's inauguration oath “under God”, two words that Sheldon refused to say. (A Political Campaign and a Candy Land Cheater)

It's time for the yearly swimming physical and Sheldon complains to Principal Peterson about it, but rebuffs Sheldon saying it is mandatory. (Teenager Soup and a Little Ball of Fib)

Sheldon makes a new appearance at his office and asks if Principal Peterson can move next door since the house is on slae. Peterson refuses to do so. (A House for Sale and Serious Woman Stuff)

Sheldon wanted to record a message for his parents, so Principal Peterson records a message of support; He reveals that Sheldon is a student who comes in once in a lifetime, and the school will be different without him and he is honored to have been a small part of it. (A Secret Letter and a Lowly Disc of Processed Meat)

Graduation time arrives and Sheldon tells him and his parents that he is a great young man and Sheldon has everything he needs, including great grade in Physical education and snitches on kids smoking. He also says Sheldon is a type of student that has never happened before; Sheldon is a valedictorian. (Graduation)

Sometime in the new school year, Principal Peterson calls George to tell him that Georgie has been cutting class. He later joins them in a drink. (An Existential Crisis and a Bear That Makes Bubbles)

He also played poker with some people, and reveals that his parents had divorced when he was roughly age 16. (A Virus, Heartbreak and a World of Possibilities)

At Nate's Roundhouse, he talks to George and is slightly envious of other people's job as he does not like having to deal with the school board. He also reveals he had tried every single version of Campbell soup. In addition, by this time, he had divorced. (The Yips and an Oddly Hypnotic Bohemian)

One day, he calls George to ask if he had seen Wayne Wilkins since he did not show up at his job. They go to his hotel room and find him. He wants George to coach the football game on Friday in Tyler, Texas. After George's coaching beats the other team, Peterson hires George back and also keeps Wayne as a coach. (An Ugly Car, an Affair and Some Kickass Football)


v · e · d
Young Sheldon Characters
Main Characters Main Sheldon Cooper  ‧  Mary Cooper  ‧  George Cooper Sr.  ‧  George Cooper Jr.  ‧  Missy Cooper  ‧  Meemaw  ‧  Jeff Difford  ‧  Billy Sparks  ‧  Amanda McAllister
Recurring and Minor Characters John Sturgis  ‧ Tam Nguyen  ‧  Paige Swanson  ‧  Veronica Duncan  ‧  Brenda Sparks  ‧  Herschel Sparks  ‧  Victoria McElroy  ‧  Evelyn Ingram  ‧  Wayne Wilkins  ‧  Hubert Givens  ‧  Sheryl Hutchins  ‧  Gene Lundy  ‧  Tom Petersen  ‧  Le Nguyen  ‧  Trang Nguyen  ‧  Mai Nguyen  ‧  Kim-Ly Nguyen   ‧  Barry Swanson  ‧  Linda Swanson  ‧  Erica Swanson  ‧  Dale Ballard  ‧  Selena  ‧  Robin Difford  ‧  Jana  ‧  Marcus Larson  ‧  June  ‧  Grant Linkletter  ‧ Linda Hagemeyer  ‧ Pat  ‧ Professor Boucher  ‧ Jim McAllister  ‧ Audrey McAllister  ‧ Amber