| Debrah Farentino | ... | Beverly Barlowe (22 episodes) |
| Kavan Smith | ... | Deputy Andy 2.0 (22 episodes) |
| Christopher Jacot | ... | Larry Haberman (21 episodes) |
| Matt Frewer | ... | Jim Taggart (17 episodes) |
| Trevor Jackson | ... | Kevin Blake (16 episodes) |
| Felicia Day | ... | Dr. Holly Marten (16 episodes) |
| Vanya Asher | ... | Lucas (12 episodes) |
| Jaime Ray Newman | ... | Tess Fontana (12 episodes) |
| Wil Wheaton | ... | Dr. Isaac Parrish (11 episodes) |
| Meshach Peters | ... | Kevin Blake (10 episodes) |
| James Callis | ... | Dr. Trevor Grant (9 episodes) |
| Barclay Hope | ... | Gen. Mansfield (8 episodes) |
| Frances Fisher | ... | Eva Thorne (8 episodes) |
| Ever Carradine | ... | Lexi Carter (8 episodes) |
| Shayn Solberg | ... | Spencer Martin (7 episodes) |
| Ming-Na Wen | ... | U.S. Senator Alice Wen (7 episodes) |
| Adrienne Carter | ... | Pilar (6 episodes) |
| Keith Wilson | ... | Baker Twin (5 episodes) |
| Bryan Wilson | ... | Baker Twin (5 episodes) |
| Tamlyn Tomita | ... | Kim Anderson (5 episodes) |
| Bridget Hoffman | ... | Computer (voice) (5 episodes) |
| Wesley Salter | ... | Technician (5 episodes) |
| Paula Lindberg | ... | Tech (4 episodes) |
| Martin Cummins | ... | Dekker (4 episodes) |
| Jordenn Thompson | ... | Jenna (4 episodes) |
| Alan Legros | ... | Seth Osbourne (3 episodes) |
| Martin Christopher | ... | (3 episodes) |
| Sonja Bennett | ... | Callie Curie (3 episodes) |
| Elias Toufexis | ... | Injured Driver (3 episodes) |
| Jackie Gonneau | ... | Computer (voice) (3 episodes) |
| Wallace Shawn | ... | Warren (3 episodes) |
| Rob LaBelle | ... | Walter Perkins (2 episodes) |
| Jennifer Clement | ... | Susan Perkins (2 episodes) |
| Zak Ludwig | ... | Brian Perkins (2 episodes) |
| Jocelyne Loewen | ... | Doris Gilmer (2 episodes) |
| Garwin Sanford | ... | Congressman Faraday (2 episodes) |
| Robert Clarke | ... | (2 episodes) |
| Michael Kopsa | ... | Doctor (2 episodes) |
| Cameron Park | ... | Dr. Rob Matthew (2 episodes) |
| Sharon Taylor | ... | Stark's Doctor (2 episodes) |
