| 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
(credit only) |
| Jesse Spencer | Dr. Robert Chase |
| Peter Jacobson | Dr. Chris Taub |
| Olivia Wilde | Thirteen |
| Michael Weston | Lucas Douglas |
| Esteban Powell | James Sidas |
| Vicki Davis | Dara Sidas |
| Jennifer Crystal Foley | Rachel Taub |
| Larry Cedar | Ed Beringer |
| Andrea Gabriel | Ronnie |
| Patrick Price | Nurse Jeffrey Sparkman |
| Dava Krause | Cashier |
| Cheryl Carter | Diana |
| Gabrielle Thomas | Woman |
| Bobbin Bergstrom | Nurse |
| Felicia Chong | Hospital Secretary
(uncredited) |
| Eric Naroyan | Cuddy's Dinner Guest
(uncredited) |