Jason Segel is an actor best known for portraying Marshall Eriksen on How I Met Your Mother. He first gained attention for his starring roles on the Judd Apatow series Freaks and Geeks and Undeclared in the early 2000s. In 2005, Segel joined the cast of CBS' How I Met Your Mother, which became a smash hit and ran for nine seasons. During that time, the actor wrote and starred in 2008's Forgetting Sarah Marshall and 2011's The Muppets. His first novel, Nightmares!, will be published in September.