Though The Walking Dead and The Big Bang Theory seem like two vastly different worlds, one actor links them in a surprising crossover: Steven Yeun. Known for his role as Glenn Rhee in The Walking Dead, Yeun makes a brief but memorable cameo in The Big Bang Theory long before his rise to stardom in the zombie apocalypse series.
Yeun’s appearance comes in season 3, episode 22, titled “The Staircase Implementation.” In this flashback episode, Leonard Hofstadter (Johnny Galecki) recalls his first experiences with Sheldon Cooper (Jim Parsons). As part of the flashback, Yeun plays Sebastian, a former resident of the apartment building who’s had enough of Sheldon’s eccentric behavior. In a brief, comedic moment, Sebastian hastily exits the building and advises Leonard to flee as well, implying that life with Sheldon is more than a little challenging. Sadly, we never learn much more about Sebastian, and the full extent of Sheldon’s bizarre behavior remains a mystery.
Yeun’s Cameo Came Just Before His Walking Dead Breakout
Steven Yeun’s cameo on The Big Bang Theory happened in 2010, just months before he would land the role of Glenn on The Walking Dead. Glenn quickly became a fan favorite, only to meet a brutal end in season 7 at the hands of Jeffrey Dean Morgan’s Negan. Before Yeun was known for surviving the zombie apocalypse, he was simply a rising star with a modest role on The Big Bang Theory.
At the time, Yeun was still in the early stages of his career, having recently moved to Los Angeles. In an interview with Interview Magazine in 2011, Yeun recalled how the role came about. He shared that his career took off rapidly, with him landing three commercials and a small role on The Big Bang Theory before his big break with The Walking Dead. He reflected on how these early projects were pivotal in setting the stage for his future success, saying:
“First thing I landed was three commercials in one sitting. It was great. Those kept me alive for a while. Then I tested for a pilot on ABC that I didn’t get, but the casting director threw me a small part on The Big Bang Theory. After that came The Walking Dead. It was a very fortunate six months.”
Yeun’s Surprising Path from Improv to Star
Before making it big, Yeun was an improv theater performer, and his role on The Big Bang Theory marked one of his earliest acting jobs outside of theater. This cameo was one of his first steps into television acting, and though his time on the show was brief, it undoubtedly helped him gain recognition. His career would later soar as he took on major roles in critically acclaimed films like Minari (which earned him an Academy Award nomination for Best Actor) and Nope, as well as a key role in the animated superhero series Invincible.
A Hidden Gem in The Big Bang Theory
While Yeun’s appearance in The Big Bang Theory was short-lived, it adds an interesting layer to his career timeline, especially in hindsight. Long before Glenn’s tragic death on The Walking Dead, he was cracking jokes in Pasadena with Sheldon and Leonard. Yeun’s brief cameo reminds us of how quickly an actor’s career can evolve from one-off TV roles to leading performances in Hollywood’s most prestigious projects.
