The 15 Best Guest Stars On Young Sheldon, Ranked

As a prequel to "The Big Bang Theory," "Young Sheldon" excels the most when it fills in the emotional gaps left by "The Big Bang Theory," portraying heartbreaking storylines teased by its predecessor, including the death of Sheldon's (Iain Armitage) father. Dramatic moments make this show stand out, but the series makes room for plenty of fun guest stars, just like "The Big Bang Theory" does

These guest stars offer comedic relief, and they shape the lives of the main characters in a way that leads them toward their storylines on "The Big Bang Theory." But which "Young Sheldon" guest stars stand out as the best across the show's seven-season run? Our rankings include a mix of cameos and lengthy guest appearances, and are based on how each character impacts the overall universe. So sit back and take a trip down memory lane as we revisit these great performances. 

15. Jason Alexander as Gene Lundy

Many "Seinfeld" fans enjoy Jason Alexander's performance as the scheming George Costanza with his many jobs. On "Young Sheldon," Alexander takes these abilities to a new level as drama teacher Gene Lundy. He has been acting for years, but his hard work has never given him the fame and fortune that he wants. He believes that taking advantage of others will get him to the top, and he can use his acting skills to help him out. His first plan unfolds in season 1, episode 16, "Killer Asteroids, Oklahoma and a Frizzy Hair Machine." Mr. Lundy is wowed by Sheldon's audition for the school play and casts him in the lead role of "Annie." What Sheldon doesn't realize is that he is telling him what he wants to hear so that way, Mr. Lundy can claim the role when Sheldon backs out.

His success with "Annie" leads to more randomized, benign schemes that actually lead to a path out of East Texas. Mr. Lundy's influence on "Young Sheldon" is minimal since his schemes don't impact the overall universe, but they do encourage the Cooper family to try different things, leading to mishaps that viewers could never imagine.

14. Ray Liotta as Vincent

The late Ray Liotta was known as a big-screen tough guy thanks to his portrayal of real-life gangster Henry Hill in "Goodfellas." His role as a bookie on "Young Sheldon" is a fun and quick nod to his career, but he makes it onto this list through the depth of his character.

Vincent's (Liotta) words prove that his backstory is bigger than his appearance at the end of season 1, episode 5, "A Solar Calculator, a Game Ball and a Cheerleader's Bosom." Meemaw (Annie Potts) tries to distract him at the slots as he begs for his money. That begging includes him calling her Constance, which is shocking since no one ever calls her that. It's clear that she and Vincent have a long history, and it could include a casino scheme, which is lightly alluded to when he reminds her that the staff are not fond of his presence. Vincent's appearance helps us realize that Meemaw has a life outside of her family, and it gives us a peek into her love for gambling, which becomes a core storyline.

13. Richard Kind as Ira Rosenbloom

Richard Kind appears three times on "Young Sheldon," and his character undergoes a lot of change, which impacts Meemaw's love life. Kind plays Ira Rosenbloom, a furniture store owner who wants to win her heart. He gladly entertains Sheldon's questions and even plans a big romantic trip. However, his efforts fall flat when she realizes that she would rather date Dr. John Sturgis (Wallace Shawn) in season 1, episode 22, "Vanilla Ice Cream, Gentleman Callers and a Dinette Set." 

This moment of rejection concludes with him sobbing as he takes her home, and it's an awkward moment that only Kind can make hilarious thanks to his exaggerated expression of pain as he loudly wails. It is somewhere between this moment and season 3, episode 5, "A Pineapple and the Bosom of a Male Friendship," that Ira realizes that his pining for Meemaw was a response to his feelings of loneliness. That's why he rejects her during the episode, and he does it with a newfound confidence that helps him realize that he doesn't want to be her backup boyfriend. She has been very nonchalant about love, and Ira's new attitude helps her realize that love should not be taken lightly. This could be why she is more careful with her relationships and why she cherishes Dale (Craig T. Nelson). 

12. Penn & Teller as Acne Vulgaris and Pus

This guest appearance will delight "The Big Bang Theory" fans, but don't expect any references to the sitcom during Penn & Teller's appearance on season 5, episode 22, "A Clogged Pore, a Little Spanish and the Future." Teller is known to many as Amy Farrah Fowler's (Mayim Bialik) father, Larry Fowler. But on "Young Sheldon," he plays Pus while Penn Jillette portrays Acne Vulgaris, with the comedic pair literally personifying Sheldon's first pimple. Sheldon is devastated, and the team responds with wisecracks about growing up and the bodily changes that come with it. This is a shock to Sheldon's whole outlook on himself because he believes that he is much more mature and grown-up than any of his peers. So, this pimple actually serves as a wake-up call, letting Sheldon know that he still has a long way to go. 

Amid the jokes about puberty and the trivia regarding pimples, Penn & Teller sneak in their signature magic, including a butterfly surprise orchestrated by Teller as Penn compares the human transformation to that of a caterpillar. It's the finishing touch to an appearance that is meant to pay homage to their illustrious career, while also making a quiet nod to "The Big Bang Theory." 

11. David Hasselhoff

David Hasselhoff's appearance does not have a big impact on "The Big Bang Theory" universe, but it's special because of how it recognizes the decades that "Young Sheldon" is set in. The Hoff appears toward the end of season 4, episode 10, "Cowboy Aerobics and 473 Grease-Free Bolts." Gene Lundy asks him to star in his cowboy exercise video when Georgie (Montana Jordan) exits the project. Hasselhoff is excited about the opportunity and even talks about his roles on "Knight Rider" and "Baywatch" as the camera shows nostalgic memorabilia, including a Michael Knight figurine. 

While he is a serious actor, Hasselhoff doesn't shy away from having fun on screen and making jokes about himself. That is why many will get a kick out of his enthusiastic appearance in the cowboy workout video. His inclusion in this episode also leads to the wrap-up of Mr. Lundy's storyline, which includes how he helped the schemer become rich and somewhat famous.

10. Ming-Na Wen as Dr. Carol Lee

"Young Sheldon" challenges Sheldon's perspective on science, the world, and family dynamics. Season 5, episode 14, "A Free Scratcher and Feminine Wiles" switches things up by focusing on workplace dynamics with the help of guest star and "Stargate Universe" actress Ming-Na Wen. Wen plays Dr. Carol Lee, a scientist who is helping Sheldon, Dr. John Sturgis, and Dr. Grant Linkletter (Ed Begley, Jr.) with a project. Dr. Sturgis and Dr. Linkletter are not sure about having her on board, but they warm up to her when they realize that they share similar interests. Meanwhile, Sheldon questions her ideas because of her gender, and her dismissal of his input makes him even more skeptical of her.

Sheldon's reaction to her involvement in this project is actually Dr. Lee's opportunity to teach him that he shouldn't use a person's gender to judge their intellect. This is probably not the first time that Dr. Lee has been dismissed for being female, and she is hoping that if she does some reverse psychology on Sheldon, it could change his perspective on women in science. It's a moment that sets the foundation for the admiration and respect that adult Sheldon (Jim Parsons) has for his wife's work on "The Big Bang Theory."

9. Steve Burns as Nathan

There are many reasons why Steve Burns' appearances are special. Like Professor Proton (Bob Newhart), Burns' Nathan is a beloved children's TV host known for "Blue's Clues." He is also the singer of the "Young Sheldon" theme song, "Mighty Little Man," but his influence on the show goes much deeper than that. 

Nathan is a "Star Trek" fan whose biggest moment happens on season 3, episode 11, "A Live Chicken, a Fried Chicken and Holy Matrimony." After letting Sheldon borrow his "Star Trek" tape, Nathan is beamed up from the Cooper residence. While narrating, adult Sheldon acknowledges that this didn't actually happen, and this lets viewers know that he is tweaking his past. This could lead fans to question his childhood memories, including his father's alleged infidelity.

Sheldon says that he really did borrow the tape from Nathan, but his later appearances could be figments of the boy's imagination. Just when Sheldon starts to feel misunderstood in regards to his passion for pop culture, Nathan suddenly pops up. It feels way too convenient, and giving Sheldon an imaginary friend also reminds us that this mature genius is still a kid. 

8. Melanie Lynskey as Professor Dora Ericson

Melanie Lynskey is known for playing bold yet thought-provoking characters. Her role as Pauline Parker in "Heavenly Creatures" frightened moviegoers, and many can't forget her time as Shauna on "Yellowjackets." While her role as Professor Dora Ericson is thought-provoking, she trades boldness for quiet strength to convince Sheldon that philosophy is worth studying in season 4, episode 7, "A Philosophy Class and Worms That Can Chase You," and episode 8, "An Existential Crisis and a Bear that Makes Bubbles." 

Their arguments cause Sheldon to doubt everything and even question his science career. This is not the outcome that Professor Ericson wants, but she knows that Sheldon needs to take this path to realize that philosophy uses critical thinking to replace doubt with understanding. She is an experienced teacher who is not fazed by the fact that Sheldon is doubting philosophy. Given his willingness to learn, she knows that he will eventually catch on and use the subject to fuel some of his greatest scientific discoveries.

7. Lance Reddick as Professor Boucher

Professor Boucher (the late Lance Reddick) is a key element of "The Big Bang Theory." Like Sheldon, this engineering teacher is strict and by-the-book. He even locks students out of his class when they're a second late. Sheldon appreciates this until he starts questioning his work. Most teachers are impressed by Sheldon's genius, but Professor Boucher is not impressed at all. He's on a mission to teach Sheldon that hard work is the true key to success, and he won't accept subpar work. 

Reddick was the secret weapon of many projects, and the same could be said about his role on "Young Sheldon" since his appearance quietly sets up a running joke on "The Big Bang Theory." The adult Sheldon (Jim Parsons) despises engineers and even looks down on his engineering pal Howard Wolowitz (Simon Helberg). Reddick's role is a well thought-out backstory to the joke that has become a hallmark of "The Big Bang Theory." 

6. Octavia Spencer as Rhonda Thomason

Meemaw is in denial over the consequences of her secret casino activities until parole officer Rhonda Thomason (Octavia Spencer) walks onto the scene during season 7, episode 10, "Community Service and the Key to a Happy Marriage." She is sentenced to 180 hours of community service, and Rhonda is making sure she completes it. However, Meemaw doesn't want to admit that she's a criminal, noting that what she did isn't really a crime. Her denial stems from the fact that she doesn't want to be labeled as a bad person, but it is Rhonda's responsibility to remind her that everyone makes mistakes. 

Of course, Meemaw doesn't go down without a fight, and that causes Rhonda to give her a serious lecture that will make you shake in your boots. While this seems like a small moment in Meemaw's life, Rhonda knows that she needs to come to terms with what she did to move forward. Spencer's scenes make up just a fraction of the episode, but she shines through her delivery of sarcastic lines that also help you understand why she is giving Meemaw the tough love that she needs. 

5. Robert Picardo as Professor Salzman

Robert Picardo has been stealing scenes throughout the "Star Trek" universe for decades, mostly by playing the holographic doctor. Like the doctor, Professor Salzman (Picardo) is all about the information during season 7, episode 2, "A Roulette Wheel and a Piano Playing Dog." The professor at the Heidelberg Institute does have a range of emotions, but he tries to keep them at bay even when scolding Sheldon for incorrect answers. While Sheldon is trying his best, Professor Salzman holds him to a higher standard set by his expectations alone, which is why he makes fun of Sheldon's education at East Texas Tech. Sheldon is appalled, but Professor Salzman believes that he is helping widen his perspective. 

Sheldon goes on to achieve great things in the world of science, and it's a potential that Professor Salzman also sees, despite the fact that he gives Sheldon a tutor who is much younger than him. However, his methods remind Sheldon of where he came from while also teaching him how to accept new ideas. This is a critical lesson as Sheldon prepares for the next step in his education.

4. Dan Byrd as Pastor Rob

Dan Byrd's role as Youth Pastor Rob gives the kids a new friend while impacting Mary's (Zoe Perry) views on morals and religion. He shakes things up by questioning the Bible during Sunday School, and he takes things a step further when he encourages the discussion of sex during season 5, episode 6, "Money Laundering and a Cascade of Hormones." Rob offers a positive approach to the topic while Mary still views it as a taboo subject, especially in church. However, Rob's views seep into Mary's subconscious when she has a spicy dream that helps her understand why Rob wants to talk about this with positivity rather than shame. 

It's a standout moment for Pastor Rob, who shares his past experiences with love, and he believes that providing the kids with knowledge is the best way to help them out. He feels they shouldn't be treated as children, and this talk helps him do just that. His perspective changes Mary's views on parenting, and it helps her become a better confidant to her kids.

3. Reba McEntire as June

June (Reba McEntire) is the ex-wife of Meemaw's boyfriend Dale, and it's a role that can be compared to her character on "Reba." She first appears on season 3, episode 15, "A Boyfriend's Ex-Wife and a Good Luck Head Rub." She charms Meemaw into becoming her friend, and that's a big deal since Meemaw doesn't really have friends. 

Like Reba, June is easy-going, but she is not quick to anger or jealousy. Instead, her insecurity quietly lingers as she comes to terms with the fact that Meemaw has the version of Dale that she wants. Her acceptance of the present takes a turn when she hurts her leg in season 5, episode 7, "An Introduction to Engineering and a Glob of Hair Gel." Meemaw has a temper, and she is upset that Dale helped June with the shower. June replies by calmly confessing her feelings, and the way that she shares her emotions proves how much respect she has for Meemaw, which is why their bond is so special.

2. Mckenna Grace as Paige Swanson

Paige Swanson (Mckenna Grace) is a huge influence on "The Big Bang Theory" despite the fact that we never get to see an adult version of Paige. She's Sheldon's worst enemy because of her prodigy status and bubbly attitude. Their constant bickering turns into a crush during season 4, episode 16, "A Second Prodigy and the Hottest Tips for Pouty Lips." This realization is a big moment because it proves that he admires the way that she challenges him, which is something that he later admires in Amy. 

Paige is also the key to Missy's (Raegan Revord) wild-child origin story. We see this when they steal George's (Lance Barber) truck in season 6, episode 16, "A Stolen Truck and Going on the Lam." During this episode, Paige implies that she likes causing trouble because no one expects that from her, and Missy feels the same way. This shows us how Missy's present connects to her past and why she made certain choices. 

1. Mayim Bialik as Amy Farrah Fowler

Amy Farrah Fowler takes the top spot on this list because her inclusion in "Young Sheldon" helps shape her and Sheldon's future beyond "The Big Bang Theory." We briefly hear her voice during seasons 4 and 5, but it's her full-fledged return in the series finale that serves as a powerful and triumphant culmination. 

Season 7, episode 14, "Memoir," gives us a glimpse into Amy and Sheldon's married life as they raise their kids. Being able to see the couple living a happy married life is a satisfying moment for fans who may have wondered what happened to their relationship after they won the Nobel Prize. Of course, their signature bickering sessions have not stopped, and this episode includes some of those fun moments. This offers details about Amy and Sheldon's children since the couple is fighting over their son's hockey game. This is the first time that details like this are shared, and while we don't see either child on camera, it does paint a satisfying picture of their family years after the event of "The Big Bang Theory."

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