William Thomas Hader Jr. (born June 7, 1978) is an American actor, comedian, and filmmaker. He was a cast member on the NBC sketch comedy series Saturday Night Live from 2005 to 2013, for which he received four Primetime Emmy Award nominations and a Peabody Award. He became known for his impressions and especially for his work on the Weekend Update segments, where he played Stefon, a flamboyant New York City nightclub tour guide. He is also known for voicing Fear in the Pixar animated film Inside Out (2015), and Flint Lockwood in Cloudy with a Chance of Meatballs (2009), and its 2013 sequel. Hader co-created the HBO dark comedy series Barry (2018–2023) with Alec Berg, in addition to playing the title role of Barry Berkman. He also served as producer, writer and director, for which his efforts garnered him eight Emmy Award nominations for the series. He won two, consecutively, for Outstanding Lead Actor in a Comedy Series. He is a star and producer of the IFC mockumentary comedy series Documentary Now! (2015–2022) along with Fred Armisen and Seth Meyers. He was Emmy-nominated for his guest role in Curb Your Enthusiasm in 2022. In film, he took supporting roles in Hot Rod (2007), Superbad (2007), Forgetting Sarah Marshall (2008), Adventureland (2009) and The BFG (2016), with leading roles in The Skeleton Twins (2014), Trainwreck (2015), and as an adult Richie Tozier in It Chapter Two (2019). He has done extensive voice work working on the Pixar films Monsters University (2013), Finding Dory (2016), Toy Story 4 (2019), and Lightyear (2022), as well as films such as The Angry Birds Movie (2016), its 2019 sequel, Sausage Party (2016) and the upcoming The Cat in the Hat (2026).