At 43 years old, Jason Segel has this physical status:
Segel's first major role was as stoner "freak" Nick Andopolis on the critically acclaimed but short-lived 1999 NBC comedy-drama series Freaks and Geeks. The series revolved around a group of suburban Detroit high school students circa 1980. Segel personally composed a song for his character, Nick, to sing to the lead female character, Lindsay (Linda Cardellini).
Segel had recurring roles on CSI: Crime Scene Investigation as Neil Jansen and on Undeclared as Eric. He played Marshall Eriksen on the CBS sitcom How I Met Your Mother; he had previously stated he would move on to other projects in 2013 when his contract expired, but was convinced to finish the series after its ninth season in 2014.
Segel made his film debut with Can't Hardly Wait in 1998. His other early feature film appearances include Slackers, SLC Punk!, The Good Humor Man, and Dead Man on Campus. In 2007, he appeared in Knocked Up, directed by Freaks and Geeks producer Judd Apatow. Segel starred in the lead role of 2008's Forgetting Sarah Marshall, a film he wrote and Apatow produced with Shauna Robertson for Universal Pictures. He also starred in I Love You, Man, which was released on March 20, 2009, by DreamWorks.
In Forgetting Sarah Marshall, Segel's character writes a "Dracula" musical performed by puppets. He also appeared in the most prominent scene containing full frontal nudity in the film. In an interview, he stated that the Dracula musical with puppets, as well as being broken up with while naked, were real experiences he wrote into the movie. Those cloth creatures were custom-made by the Jim Henson Company, and the experience emboldened Segel to pitch his concept for a Muppets movie. Segel performed a song from the film, "Dracula's Lament", on the 1000th episode of The Late Late Show with Craig Ferguson.
For the 2010 comedy Get Him to the Greek, Segel co-wrote most of the soundtrack's music which was performed by the fictional celebrity singer, Aldous Snow, including Infant Sorrow. He also appeared on The Late Late Show with Craig Ferguson and sang an original song entitled "Wonky Eyed Girl".
In 2010, he voiced Gru's arch-rival Vector in the Universal's CGI animated film, Despicable Me and appeared as "Horatio" in a fantasy comedy film Gulliver's Travels directed by Rob Letterman and very loosely based on Part One of the 18th-century novel of the same name by Jonathan Swift. Segel appeared in Bad Teacher, starring Cameron Diaz, which opened in June 2011. He played gym teacher and thwarted suitor Russell Gettis. Along with Nicholas Stoller, Segel approached Disney in 2007 to write the latest Muppets film. Disney was unsure on how to take the request, as Segel had just done frontal nudity in Forgetting Sarah Marshall, but after realizing that he was a fan, the project was approved. Segel stated that he wanted to do the film because the last film in the series to be released in theaters was Muppets from Space in 1999, and he felt that the younger generation was missing out on enjoying one of his childhood favorites.
Segel decided not to star in the sequel to The Muppets, Muppets Most Wanted. He filmed The Five-Year Engagement, with Emily Blunt, in spring 2011, in Michigan, and the film was released on April 27, 2012.
In 2013, Segel revealed he was working on a series of young adult novels, based on a story he conceived when he was 21. In the fall of 2014, the first novel of the series Nightmares!, co-written with Kirsten Miller, was released, with the followup coming out the following year.
In 2015, Segel received praise for his portrayal of the late author David Foster Wallace in the independent biographical drama film The End of the Tour. For his performance, he earned an Independent Spirit Award nomination for Best Male Lead.
In 2017, Segel and Miller released their first young adult novel, Otherworld. Segel created and starred in the American drama television series Dispatches from Elsewhere, which premiered on March 1, 2020, on AMC.
In 2019, Segel starred in Our Friend based on Matthew Teague's 2015 essay "The Friend".