The actors agreed to do the third film as long as there wasn't a fourth movie. Bradley Cooper, Ed Helms, and Zach Galifianakis felt the story had lost its momentum. Cooper took convincing to do the project from Galifianakis.
Grant Holmquist, who performed the role of baby Tyler/Carlos in The Hangover (2009), returns to portray toddler Tyler/Carlos in this film.
Bradley Cooper, Ed Helms, and Zach Galifianakis were all reportedly paid $15 million plus a back-end deal to return for this movie.
In 2012, Zach Galifianakis lost so much weight that he had to wear a prosthetic belly for this film.
Because of the timing and length of this shoot, Ed Helms needed more time off from his then-regular role as Andy Bernard on The Office (2005) for this film than he had for either of the first two films of the trilogy. The show ended up having Andy take an extended and unauthorized journey from his job after he salvaged the criminal misdeeds of his father.
Todd Phillips: Playing as Mr. Creepy again in the motel room in a bathrobe paying off a prostitute as Mr. Chow is parachuting across his Las Vegas hotel room window.