He became known for his impressions and especially for his work on the Weekend Update segments, where he played Stefon Meyers, a flamboyant New York City nightclub tour guide.

1956)[5] and air cargo company owner, restaurant manager, truck driver, and occasional stand-up comedian William Thomas Hader (b.

[12] He was unable to gain admission to top film schools because of his "abysmal" grades, so he enrolled at The Art Institute of Phoenix,[13] and later Scottsdale Community College.

[12] He was a PA on the documentary Empire of Dreams: The Story of the Star Wars Trilogy (2004) and the feature films James Dean (2001), Spider-Man (2002) and Collateral Damage (2002).

[20] He was briefly a PA and stage manager on Playboy TV's sexual fantasy show Night Calls,[21][22][23] but soon quit as he feared it would disappoint his parents.

[26][27] After attending one of their backyard shows, Mullally told Hader she wanted to discuss him with Lorne Michaels of Saturday Night Live (SNL).

[29] His list of impressions includes Vincent Price in the Variety Vault sketches, Keith Morrison, Harvey Fierstein, Al Pacino, Rick Perry, John Malkovich, James Carville, Julian Assange, Eliot Spitzer, Alan Alda, Clint Eastwood, and Charlie Sheen.

On July 19, 2012, Hader received his first nomination for a Primetime Emmy Award for Outstanding Supporting Actor in a Comedy Series for his work on SNL.

[36] His role in Superbad helped boost his public awareness and allowed him to appear on mainstream programs like Total Request Live, The Tonight Show, and MTV's Video Music Awards.

in the Judd Apatow directed comedy Knocked Up,[37] the acid-taking mechanic Dave in Hot Rod alongside SNL castmate Andy Samberg,[38] and a recumbent biker in The Brothers Solomon starring Will Arnett and Will Forte.

[40][41] His involvement in the series stems from his friendship with Matt Stone; the two held a similar sense of humor and Hader began going on writers' retreats with the staff.

He also made several short films, including Back in the Day, Sounds Good to Me: Remastering the Sting, and The Jeannie Tate Show, with SNL writer Liz Cackowski and then-wife Maggie Carey.

Also in 2008, Hader appeared on Tim and Eric Awesome Show impersonating the recurring character James Quall on the episode "Jazz".

He lent his voice to his first video game role in Grand Theft Auto IV, which also featured his SNL castmates Jason Sudeikis and Fred Armisen.

He voiced a gazelle in Ice Age: Dawn of the Dinosaurs and appeared in the fantasy film Night at the Museum: Battle of the Smithsonian in 2009 as Major General George Armstrong Custer.

[45] Hader took on the voice role of Professor Impossible on the fourth season of The Venture Brothers (2010–2013), a part originated by Stephen Colbert.

[47] TCM asked him if he would like to host its summer Essentials Jr. showcase that introduces younger audiences to seminal movies from the golden age of Hollywood and international cinema.

The films he chose included Singin' in the Rain (1952), Bringing Up Baby (1938), The Band Wagon (1953), and The Lavender Hill Mob (1951) and King Kong (1933) .

Hader starred in a dramatic role in the 2014 film The Skeleton Twins, opposite Kristen Wiig, with whom he worked on Saturday Night Live.

However, Hader, alongside John Lithgow, Lucas Neff, Neil Patrick Harris, and Judy Greer, left the project after their characters were redesigned.

[54] Also in 2015, Hader reunited with fellow SNL alumni Fred Armisen and Seth Meyers for the IFC mockumentary series Documentary Now!, wherein he was an actor and a writer.

In December 2015, Drew McWeeny of HitFix reported that the voice of BB-8 in Star Wars: The Force Awakens was supplied by Hader and Ben Schwartz, both credited as "BB-8 vocal consultants" in the film.

[55] Hader also voiced multiple characters in YouTube channel Bad Lip Reading's parodies of the Star Wars original trilogy.

[57] In 2018, Hader co-created (with Alec Berg) and began starring in the HBO dark comedy series Barry, for which he received eight Primetime Emmy Award nominations as producer, writer, director, and actor.

[59] In 2019, he voiced Leonard in The Angry Birds Movie 2, Axel the Carnie in Toy Story 4, The Wanderer in 4 episodes of The Dark Crystal: Age of Resistance, and played Nick Kringle in Noelle.

[61] That same year he had a cameo role as a UPS driver in the Ari Aster directed surrealist tragicomedy Beau is Afraid (2023) starring Joaquin Phoenix.

"[62] In March 2024, it was announced that Hader will star in the upcoming animated remake of the Dr. Seuss children's book The Cat in the Hat, in which he will voice the titular character and serve as an executive producer.

[63] Hader and Mindy Kaling did not return to voice their roles as Fear and Disgust in Inside Out 2 reportedly due to pay disputes.

[64] Hader has said that his comedy influences included Woody Allen,[65][66][67] Monty Python, Alan Alda, Mel Brooks and Eddie Murphy.

He named works by Tobias Wolff, Fyodor Dostoevsky, William Faulkner, Richard Ford, George Saunders, and Jun'ichirō Tanizaki as influences.