Elias Koteas
Colonel Marks (13 eps)
Michelle Borth
Dr. Rebecca Gordon (13 eps)
Luke Mably
Dr. Simon Hill (13 eps)
Deborah Kara Unger
Major Grace Pedersen (13 eps)
Terry Chen
Captain Bobby Trang (13 eps)
Arnold Pinnock
Commander Will Royal (13 eps)
Lisa Berry
Capt. Pam Everwood, RN (11 eps)
Jack Murray
Soldier Five (1 eps)
Mena Massoud
Salman Zawab (1 eps)
Martin Roach
Lt. Cliffgood (1 eps)
Rob Stewart
Major Kenneth Winacott (1 eps)
Greg Bryk
Master Sgt. Edward Farringdon (1 eps)
Shauna MacDonald
Mrs. Marks (voice) (1 eps)
Billy MacLellan
Pvt. Nestrom (uncredited) (1 eps)