| Jeff Kahn | Snooty Waiter |
| Robert Downey Jr. | Kirk Lazarus |
| Anthony Ruivivar | Platoon Sergeant Shot in Head |
| Jack Black | Jeff Portnoy |
| Jay Baruchel | Kevin Sandusky |
| Brandon T. Jackson | Alpa Chino |
| Ben Stiller | Tugg Speedman |
| Eric Winzenried | Chopper Pilot |
| Steve Coogan | Damien Cockburn |
| Valerie Azlynn | Damien's Assistant |
| Matt Levin | Cameraperson |
| David Pressman | First Assistant Director |
| Amy Stiller | Script Supervisor |
| Danny R. McBride | Cody (as Danny McBride) |
| Dempsey Silva | Special Effects Assistant |
| Bill Hader | Studio Executive Rob Slolom |
| Nick Nolte | Four Leaf Tayback |
| Jeff Weidemann | Speedman Assistant #1 |
| Nadine Ellis | Speedman Assistant #2 |
| Rachel Avery | Speedman Assistant #3 |
| Darryl Farmer | Alpa's Posse |
| Rod Tate | Alpa's Posse |
| Maria Menounos | Herself |
| Tyra Banks | Herself |
| Christine Taylor | Rebecca |
| Jel Galiza | Speedman's Chef |
| Andrea De Oliveira | Speedman's Trainer |
| Matthew McConaughey | Rick Peck |
| Yvette Nicole Brown | Peck's Assistant |
| Reggie Lee | Byong |
| Trieu Tran | Tru |
| Brandon Soo Hoo | Tran |
| J. Thomas Chon | Half Squat |
| Jacob Chon | Half Squat |
| Tom Cruise | Les Grossman |
| Mini Anden | Grossman's Secretary |
| Mike Hoagland | Grossman's Assistant |
| Jon Voight | Himself |
| Jennifer Love Hewitt | Herself |
| Jason Bateman | Himself |
| Lance Bass | Himself |
| Alicia Silverstone | Herself |
| Denise Bradley | Academy Award Guest |
| Ella Christopher-Pantoliano | Stewardess |
| The Mooney Suzuki | Themselves |
| Kathy Richards | Herself (as Kathy Hilton) |
| Mickey Rooney | Old Man Carruthers |
| Kaylee Dodson | Sack Race Girl (uncredited) |
| Jasmine Dustin | Trophy presenter (uncredited) |
| Eric Feliciano | Academy Awards Audience Member (uncredited) |
| Miko Hughes | Radio DJ (uncredited) |
| Jillian Johnston | Four Leaf's Date (uncredited) |
| Tobey Maguire | Himself (uncredited) |
| Anya Monzikova | Trophy presenter (uncredited) |
| Chad Mountain | Agency Assistant (uncredited) |
| Kevin Pollak | Head Priest (uncredited) |
| Becca Sweitzer | Go Go dancer (uncredited) |
| Kyle Willshire | Academy Awards Audience Member (uncredited) |
