| Hugh Laurie | Dr. Gregory House |
| Lisa Edelstein | Dr. Lisa Cuddy |
| Omar Epps | Dr. Eric Foreman |
| Robert Sean Leonard | Dr. James Wilson |
| Jennifer Morrison | Dr. Allison Cameron |
| Jesse Spencer | Dr. Robert Chase |
| Greg Grunberg | Ronald Neuberger |
| Keri Lynn Pratt | Amy Errington |
| Adam Busch | Tony |
| Ron Perkins | Dr. Ron Simpson |
| Yvette Nicole Brown | Ellen Stambler |
| Howard Hesseman | Henry Errington |
| Craig Patton | 2nd Table East |
| Susan Grace | 1st Table North |
| Noel Conlon | 1st Table East |
| Marcie Lynn Ross | 2nd Table West |
| Jean St. James | Cecile |
| Stephen DeCordova | 2nd Chief Surgeon
(as Stephen Decordova) |
| Bobbin Bergstrom | ER Doctor |
| Michael A. Casey | Heart surgeon
(uncredited) |
| Rosemary Garris | ER Doctor
(uncredited) |
| Alexander Hall | Doctor
(uncredited) |
| Brianna Konefall | Tony's Stepmom
(uncredited) |
| Kitty Kreidler | Laura Neuberger
(uncredited) |