He has appeared in films such as Blades of Glory (2007), Hot Rod (2007) and Teenage Mutant Ninja Turtles (2014).
He is a prolific voice actor with film roles including Ratatouille (2007), Monsters vs.
altogether, until his agent persuaded him to audition for the pilot for Arrested Development.
In 2003, Arnett found mainstream success in television when he played George Oscar "Gob" Bluth II in the Fox comedy series, Arrested Development and in 2006 he was nominated for his first Emmy He also played Max the Magician in Sesame Street, in a nod to Gob Bluth's penchant for using Europe's "The Final Countdown" during his magic shows.
Arnett has referred to 2000, the year after that show was cancelled, as "the darkest year of [his] life" and he admits that he "didn't get a lot of work" and "drank those years away." In 2001, Arnett was cast in the CBS television pilot, Loomis as the slacker brother of a local news reporter (Cheri Oteri), that was not picked up.
In 2002, Arnett was cast in a fourth television pilot which was for the CBS sitcom Still Standing, which was picked up and ran for several seasons, but his character was cut from the series after the pilot.
In March 2012, Mansome, Arnett’s first executive-producer credit with Jason Bateman, was announced as a Spotlight selection for the Tribeca Film Festival.
He appeared in a major supporting role in the basketball comedy Semi-Pro, his second film with Ferrell.
In 1999, Arnett starred in another pilot for The Mike O'Malley Show on NBC as the protagonist's friend Jimmy.
The show was picked up, but was canceled after only two episodes.
Arnett's distinctive gravelly voice has earned him voice-over work for CBS television promos, film trailers and numerous advertisements, including Lamisil medication. in Universal's Knight Rider, a sequel to the popular 1980s television series. In the Fox animated comedy series Sit Down, Shut Up, he voiced Ennis Hofftard, a bodybuilder who teaches English and always attempts to chase women.
Perhaps most recognizable is Arnett's voice saying, "It's not more than you need, just more than you're used to" in ads for GMC trucks. Arnett lent his voice to Batman in the film The Lego Movie, making him the second Canadian actor to portray Batman in a film, after Bruce Greenwood first did so in the animated film Batman: Under the Red Hood; Arnett reprised the role in The Lego Batman Movie, a spin-off of The Lego Movie released in 2017. In April 2007, during a panel hosted by The Paley Center for Media, talk show host Conan O'Brien and his writing staff named Will Arnett as one of their three all-time favorite guests, sharing the honor with Norm Macdonald and Harland Williams.