| cast |
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| Series Regulars | |||
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| Brian McNamara | Brian McNamara as Colonel Michael Holden | Brigid Brannagh | Brigid Brannagh as Pamela Moran |
| Catherine Bell | Catherine Bell as Denise Sherwood | Drew Fuller | Drew Fuller as Trevor LeBlanc |
| Jeremy Davidson | Jeremy Davidson as Chase Moran | Katelyn Pippy | Katelyn Pippy as Emmalin Holden |
| Kim Delaney | Kim Delaney as Claudia Joy Holden | Sally Pressman | Sally Pressman as Roxy LeBlanc |
| Sterling K. Brown | Sterling K. Brown as Roland Burton | Terry Serpico | Terry Serpico as Frank Sherwood |
| Wendy Davis | Wendy Davis as Lt. Colonel Joan Burton | | |
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| Recurring & Guests | |||
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| David Call | David Call as Mac | Harry Hamlin | Harry Hamlin as Professor Chandler |
| Kelly Hu | Kelly Hu as Jordana Davis | Lee Tergesen | Lee Tergesen as Officer Boone |
| Matthew Glave | Matthew Glave as Lt. Colonel Evan Connors | Mayte Garcia | Mayte Garcia as Jennifer Connor |
| Paul Wesley | Paul Wesley as PFC Logan Atwater | Seamus Dever | Seamus Dever as Dr. Chris Ferlinghetti |