| Pro | Lester | Sheehan | The head of the therapy session. |
| | Emily | | A nurse. |
| | Dr. | Axelrod | A psychologist. |
| | Edward | Daniels | Protagonist. A U.S. Marshall. AKA: Teddy. |
| | Dolores | Chanal | Teddy's wife. Deceased. AKA: Linda Cox. |
| | Rachel | Solando | The missing patient. |
| | Andrew | Laeddis | The mystery patient. |
| | | | Day 1 |
| 1 | Gil | Restak | A fisherman. |
| | Nikos | Costa | The boat owner. |
| | Charles | Aule | Teddy's new partner. AKA: Chuck. |
| 2 | Mcpherson | | A deputy warden. |
| | John | Cawley | The institution's chief of staff. |
| | Vincent | Gryce | A patient who kills all of his relatives. |
| 3 | Margaret | Cawley | Dr. Cawley's wife. AKA: Peggy. |
| | Kerry | Marino | One of the nurses. |
| | Mr. | Ganton | The head of orderly. |
| 4 | Glen | Miga | One of the orderlies. |
| | Trey | Washington | One of the orderlies. |
| 5 | Colonel | Spivey | The owner of the "Great Room". |
| | Jeremiah | Naehring | Dr. Cawley's colleague. |
| | Bibby | Luce | Trey's roommate. |
| | | | Day 2 |
| 7 | Ken | Gage | One of the patients. |
| | Peter | Breene | One of the patients. |
| | Leonora | Grant | One of the patients. |
| | Arthur | Toomey | One of the patients. |
| | Bridget | Kaerns | The patient who killed his own husband. |
| | Julie | Taketomi | Chuck's wife. |
| 8 | Maggie | Moonpie | The patient who has a scar in her throat. |
| 9 | Hurly | | The senator. |
| | George | Noyce | The patient that Teddy beat. |
| | Bobby | Farris | The warden at Renton. |
| 10 | Dorish | Walsh | The first test patient. |
| | Dr. | Brotigan | The neurosurgeon. |
| 11 | James | Solando | Rachel's husband. AKA: Jim. |
| 12 | Marie | | Cawley's ex-lover. |
| 13 | Ben | | One of the orderlies. |
| | Frankie | Gordon | Another sergeant from Intel. |
| | | | Day 3 |
| 14 | Harry | | The institution's facilitator. |
| | Mr. | Willis | The institution's admin. |
| | Paul | Vingis | The patient who killed his brother's wife and kids. |
| | Fred | Baker | The kid that Teddy helped. |
| 15 | Litchfield | | One of the patients. |
| | Willy | | One of the patients. |
| 16 | Al | | One of Dr. Cawley's men. |
| 17 | Byron | | One of the wardens. |
| | | | Day 4 |
| 19 | Tootie | Vicelli | The soldier that Teddy served with in the army. |
| 21 | Edward | Laeddis | Andrew's son. Deceased. |
| | Daniel | Laeddis | Andrew's son. Deceased. |
| | Rachel | Laeddis | Andrew's daughter. Deceased. |
