William Thomas Hader Jr. (born June 7, 1978) is an American comedian, actor, voice actor, producer and writer. He is best known for his work on Saturday Night Live (2005–2013), for which he has received three Emmy nominations, South Park (2009–present), and his parody series Documentary Now! (2015–present).
He is also known for his supporting work in comedy films, such as You, Me and Dupree (2006), Hot Rod (2007), Superbad (2007), Forgetting Sarah Marshall (2008), Tropic Thunder (2008), Night at the Museum: Battle of the Smithsonian (2009), Paul (2011), Men in Black 3 (2012), and Maggie's Plan (2015). He has also had lead voice roles in Cloudy with a Chance of Meatballs (2009), Inside Out (2015), and The Angry Birds Movie (2016) as well as lead roles in the dramedy The Skeleton Twins (2014) and the romantic comedy Trainwreck (2015). He has performed voice roles in Pixar films, including Inside Out, Monsters University, and Finding Dory.