Jason Jordan Segel (born January 18, 1980) is an American actor, author, and screenwriter. He is known for his role as Marshall Eriksen in the CBS sitcom How I Met Your Mother, as well as for his work with producer Judd Apatow on the television series Freaks and Geeks and Undeclared, and for films including Forgetting Sarah Marshall, Sex Tape, Knocked Up, The Muppets and The Five-Year Engagement.