Lieutenant/Lt. Commander/Commander Harmon "Harm" Rabb, Jr.
Major/Lt. Colonel Sarah "Mac" Mackenzie
Lieutenant(J.G.)/Lieutenant Bud Roberts
Ensign/Lieutenant(J.G.)/Lieutenant Harriet Sims-Roberts
Admiral A.J. Chegwidden
Commander Sturgis Turner
Lieutenant Loren Singer
Lt. Commander Mic Brumby
CIA Agent Clayton "Clay" Webb
Other Recurring Characters