Matthew Modine Guest Stars on The Simpsons, Diagnoses Bart

In a notable crossover of talent, actor Matthew Modine recently lent his voice to an episode of the long-running animated series The Simpsons. Modine, known for diverse roles including those in Stanley Kubrick’s “Full Metal Jacket,” Christopher Nolan’s “Oppenheimer,” and particularly his portrayal of Dr. Martin Brenner in Netflix’s “Stranger Things,” appeared in the Season 37 episode titled “Bad Boys… For Life?”. In this special appearance, Modine’s character, Dr. Leonard Stern, a state psychologist, controversially diagnoses Bart Simpson as a “psycho.”

Matthew Modine’s Role as Dr. Leonard Stern

Matthew Modine took on the role of Dr. Leonard Stern, a state psychologist brought in to examine Bart Simpson’s behavioral issues. Modine himself acknowledged that the character was a subtle nod to his Dr. Brenner role from “Stranger Things,” often affectionately referred to as “Papa” by the supernaturally gifted Eleven. His involvement in the iconic animated series was, for Modine, an honor to be part of such a historic show. He expressed his enthusiasm for the role, stating he would have done anything asked of him for the part.

Bart’s Troubling Diagnosis in “Bad Boys… For Life?”

The episode, which aired on November 2, 2025, served largely as a flashback, with Marge recounting past events concerning the escalating tensions between Bart and Homer. When conventional methods and even Dr. Hibbert proved ineffective in managing their tumultuous relationship, Marge sought the help of a specialist. This led to the introduction of Dr. Stern, whose initial approach to Bart appeared sympathetic. He noted, “Bart, you’re a very special boy. And sometimes special boys have to go to special places.”

However, Dr. Stern’s perspective dramatically shifted after he viewed a video depicting Bart’s disruptive antics and tormenting of Homer. Following this, the psychologist concluded that Bart was, in fact, a “psycho” and subsequently obtained a special court order to have him removed. The episode delved into the origins of Bart’s misbehavior, exploring whether he truly is a “bad seed”.

Behind the Scenes: Modine’s Experience and Al Jean’s Departure

Working on The Simpsons proved to be a fast-paced experience for Modine. He praised writer Al Jean for his efficiency and clear vision during the recording process. Modine described the experience as “getting on board a really amazing horse, and just holding on,” highlighting Jean’s rapid and precise directorial style.

“Bad Boys… For Life?” holds additional significance as it marked a pivotal moment behind the scenes. This episode was the final one for which Al Jean served as the sole showrunner for The Simpsons. Jean, a foundational figure with the show since its inception in 1989, had been a co-showrunner for Seasons 3 and 4 before becoming the sole showrunner from Season 13 onward. While stepping down from the lead showrunner role, he confirmed he will remain involved with the series as a writer and producer. Matt Selman, who has been a showrunner since Season 23, is now the sole showrunner for the series moving forward. Jean has also hinted at pursuing other projects, including a collaboration with Jon Lovitz on “The Critic”.

Conclusion

Matthew Modine’s guest appearance as Dr. Leonard Stern brought a uniquely chilling dynamic to Springfield, particularly with his “Stranger Things”-esque diagnosis of Bart Simpson. This memorable episode not only provided a fresh take on Bart’s perennial troublemaking but also marked a significant transition in the show’s leadership with Al Jean’s change in role. Fans can revisit this episode to see Modine’s distinctive performance and reflect on a new chapter for The Simpsons.