Jason Jordan Segel (/ˈsiːɡəl/ SEE-gəl; born January 18, 1980) is an American actor, comedian, producer, and screenwriter. He is best known for his role as Marshall Eriksen in the CBS sitcom How I Met Your Mother, as well as for his work with director and producer Judd Apatow on the television series Freaks and Geeks and Undeclared, and for the critically successful comedies in which he has starred, written, and produced.

Segel has starred in many films, including Knocked Up (2007), Forgetting Sarah Marshall (2008), I Love You, Man (2009), Despicable Me (2010), Bad Teacher (2011), Jeff, Who Lives at Home (2011), The Muppets (2011), The Five-Year Engagement (2012), This Is 40 (2012), Sex Tape (2014), The Discovery (2017), and Our Friend (2019). His performance as the late author David Foster Wallace in the 2015 film The End of the Tour was met with critical acclaim, earning him a nomination for the Independent Spirit Award for Best Male Lead.

In 2023, he began starring as a therapist in the comedy drama series Shrinking.

Early life
Segel was born on January 18, 1980, in Los Angeles, California, to Jillian (née Jordan; born 1952) and Alvin Segel, a lawyer. He grew up in the Pacific Palisades neighborhood. He has an older brother, Adam, and a younger sister, Alison.

Segel's father is Jewish, whereas his mother is of English, Scottish, Irish, and French descent. He has stated that he was raised Jewish, as well as "a little bit of everything". Segel went to Hebrew school and had a Bar Mitzvah ceremony, and also attended St. Matthew's Parish School, a private Episcopal school.

Following elementary school and middle school, Segel completed his high school studies at Harvard-Westlake School, where his 6 ft 4 in (1.93 m) frame helped him as an active member of the 1996 and 1997 CIF state champion boys' basketball team. He won a slam dunk contest in high school and he was nicknamed "Dr. Dunk." He was a backup to the team's star center, Jason Collins, who went on to play in the NBA.