Nicholas Stoller Director Jason Segel Peter Bretter Actor, Screenwriter Kristen Bell Sarah Marshall Actor Mila Kunis Rachael Actor Russell Brand Aldous Actor Bill Hader Brian Actor Liz Cackowski Liz Actor Jack McBrayer Darald Actor Taylor Wily Kemo Actor Da'Vone McDonald Dwayne the Bartender Actor Steve Landesberg Dr. Rosenbaum Actor Jonah Hill Matthew the Waiter Actor Paul Rudd Chuck Actor Kala Alexander Greg Actor Branscombe Richmond Keoki Actor Billy Bush Self Jason Bateman Animal Instincts Detective Actor William Baldwin Detective Hunter Rush Actor Judd Apatow Producer Shauna Robertson Producer Richard Vane Executive Producer Rodney Rothman Executive Producer Russ T. Alsobrook Cinematographer William Kerr Film Editing Lyle Workman Original Music Jackson De Govia Production Design K.C. Fox Set Decoration Leesa Evans Costume Design Jeanne McCarthy Casting Scott Meehan Art Director