Jason wrote the screenplay for the movie, Forgetting Sarah Marshall. Coincidently, his character in the TV show, How I Met Your Mother is named Marshall.
Jason's movie career has included appearances in 2003's Certainly Not a Fairytale and 2006's Bye Bye Benjamin.
Jason is terrified of heights.
As of 2008, Jason lives in a gothic four-bedroomed house in West Hollywood, close to the famous hotel, The Chateau Marmont.
At the age of 21, Jason wrote a script for a show that he called Nightmares Beware. The script was purchased but never made it as far as production. In order for the studio to buy it, he had to promise not to star in it.
Jason shocked his mother so much by appearing fully nude in the movie Forgetting Sarah Marshall that she left the screening of the movie in tears, not returning for several minutes. It was at this point that Jason realised not warning her of his nude role prior to the screening may not have been as funny as he had anticipated!
Jason has loved puppets since he was a child, so it was a dream come true when the Henson company designed the puppets for his movie, Forgetting Sarah Marshall.
Jason was a gifted basketball player during High School, winning a state championship and earning himself the nickname Dr. Dunk. Jason enjoyed playing the piano when he was not on the basketball court.
Jason is a big fan of Disney and he loves Disneyland theme parks.
Jason has a sister, Alison, born March 9, 1986.
Jason has a large scar on his leg.
At 6'4", Jason is the tallest of the How I Met Your Mother cast.
Jason is openly Jewish.
Jason once wrote a song for his character to sing in an episode of Freaks and Geeks.
When season one of How I Met Your Mother wrapped up, Jason bought a house in Hawaii for a month.
Jason attended the Harvard-Westlake School at the same time as Jake Gyllenhaal.
In 1998, Jason starred with his Freaks & Geeks co-star, Linda Cardellini, in Dead Man on Campus. Their characters were boyfriend and girlfriend. After starring in Freaks & Geeks, the two actually became a couple in reality.
Jason was cast as Marshall in How I Met Your Mother because the creators were fans of Freaks & Geeks.
Jason was nominated with his Freaks & Geeks castmates for a Young Artist Award in the category of "Best Performance in a TV Series - Young Ensemble."
Jason is the middle child of three children.
When he was young, two of his biggest influences were Robert DeNiro and James Dean.
Jason's acting career started after attending an audition he was told was fake. It turned out that the 'mock' audition was real, and the 'fake' casting agent was really the president of Paramount.
According to Jason, he always knew he wanted to be an actor.
Jason enjoys listening to classic rock and reggae music.
Jason and his friend Brian were wrestling in the pool, and Brian's finger went into Jason's eye. He ended up having to go to the doctor. Luckily the damage wasn't permanent!
Jason Segel: (On being given writing tips by Judd Apatow) He literally took me into his office and sat me down and showed me how to do an outline and how to do a beat sheet and how to write a script. He said, "You're kind of a weird guy, and that's the only way you're going to make it".
Jason Segel: (On nudity in movies & his full frontal performance in 'Forgetting Sarah Marshall') One of the great things about female nudity is that at least they have the comfort of knowing that men have all different kinds of preferences. There's not that many women out there who like small penises, but I think I came out all right. Let's see if I ever get a date.
Jason Segel: (On the inspiration for 'Forgetting Sarah Marshall') I always have awkward relationships with the ladies for whatever reason. I don't know and so here we are. I was able to sort of take all of those terrible, terrible, terrible dates and turn them into a money making venture.
Jason Segel: (On why he is excited to be writing the new Muppets Script) I've just grown a little disappointed with Muppets in the Old West, Muppets Under Water and all these weird concept movies. I just want to go take it back to the early 80's, when it was about the Muppets trying to put on a show. That's what I'm trying to bring back.
Jason Segel: (On his favorite Muppet) Kermit was the Everyman, the original Tom Hanks, but I have a special place in my heart for Fozzie Bear. The classic borderline hacky entertainer.
Jason Segel: (On being recognised following 'How I Met Your Mother') You know, we got a little taste of it when the Freaks and Geeks DVDs came out. There was a little resurgence of people having seen the show. But this is – it's getting more and more noticeable for the first time. Like in restaurants or things like that, people will come up to the table. But, I sort of love it. You're doing the job so that people will enjoy it and like your work, so I welcome it.
Jason: I'm better looking in person.
Jason: (discussing how he felt after starring in two flops) It's always a very scary feeling. But then, what was really cool was when this show came along – How I Met Your Mother – there was something different about it. I'm used to feeling like the underdog.