During an interview on Attack of the Show, Adam Mckay claimed he was initially reluctant to cast Mark Wahlberg. He worried that a more traditional actor like Wahlberg couldn't keep up with a cast famous for improvising. Mckay later admitted that Wahlberg adapted perfectly within minutes of shooting the first scene.
Just before Terry and Allen are forced to turn over their evidence to the SEC in New York, there is a cut scene of a skyline. Since everything takes place in New York, one assumes that it's the New York skyline. However, if you look closely there are two tall buildings: the John Hancock building and the Prudential Tower. Both are located in Boston, Massachusetts, where Mark Wahlberg grew up.
The role of Detective Highsmith was originally written with Michael Chiklis in mind. However, when offered the part, he turned it down to avoid typecasting after the series finale of his acclaimed police drama, The Shield (2002).
In 'The Departed', Mark Wahlberg has his famous line, "I'm the guy who does his job; you must be the other guy". Years later, he plays alongside Will Ferrell as a team of half-witted cops in the movie 'The Other Guys".
During an episode of Big Brother, the house guests competed in a luxury challenge to see an advance screening of the film. Although they weren't actually in the house, both Will Ferrell and Mark Wahlberg made an on-screen video appearance.