| Joseph Fiennes | Mark Benford |
| John Cho | Demetri Noh |
| Jack Davenport | Lloyd Simcoe |
| Zachary Knighton | Dr. Bryce Varley |
| Peyton List | Nicole Kirby |
| Brían F. O'Byrne | Aaron Stark |
| Courtney B. Vance | Stanford Wedeck |
| Sonya Walger | Dr. Olivia Benford |
| Christine Woods | Janis Hawk |
| Peter Coyote | President Dave Segovia |
| Talia Balsam | Surgeon General Anita Ralston |
| Lee Thompson Young | Al Gough |
| Barry Shabaka Henley | Agent Shelly Vreede |
| Navi Rawat | Maya |
| Barbara Williams | Vice President Joyce Clemente |
| Glynn Turman | Senator Noland |
| Michael O'Neill | CIA Director Keller |
| Michael Cavanaugh | SETI Chairman Warren Moore |
| Frank John Hughes | Press Secretary |
| Mel Rodriguez | Oscar Obregon |
| Omid Abtahi | Ed Fiore |
| Amy Rosoff | Marcie Turoff |
| Emerson Brooks | Connelly |
| J. Michael Silver | Randy |
| Michelle Tuzee | Broadcaster |
| Mieko Hillman | Renee Garrigos |
| Christopher Mack | Little Boy - Renee's Son |
| Scott Kelly Galbreath | Jim |
| Micole Mercurio | Maureen |
| Nilson De Macena | Tae Kwon Do Instructor |
| Rick L. Dean | Doctor |
| Tara Redfield | Waitress |
| Jacob Taylor | Agent Munoz |
| Gina Torres | Felicia Wedeck |