John Ralston

as Clark

as Professor Cleary (2 episodes)

as Christopher Parsons (1 episode)

as Werner

as George Venturi

as Dr. Modan

as MCRN Admiral (1 episode)

as Derek Longbrake (6 episodes)

as William Rathcart

as FDA Chairman

as Whit Randolph (2 episodes)

as Tom O'Neill

as Greg Dale

as Gregor

as Mr. Chandler (1 episode)

as Paul (2 episodes)

as MacGregor

as Stevens

as Detective Jakobsson

as Stuart Wells

as Reuben

as Tom Miller

as Richard

as Walter "Walt" Jackson

as John Buckhout