DEA Agent Mack Boyle (2 episodes)

Leo Steinem

Dr. Leon Bechley (13 episodes)

Hugh Crain (10 episodes)

Dr. Brown

Emmett Crawford (15 episodes)

Nathan M. Singer (5 episodes)

Oswald Hinge

Dr. White

Self (1 episode)

Russ Skokie (11 episodes)

Dan Sullivan (10 episodes)

Nicholas Coates (8 episodes)

Bruce Komiske

Gabriel

Sidney Kroll

Ian

Professor Adams / Subject #30

George McAlpine

Crawford Haines

Nathan Ford (77 episodes)

Richard Ledge

Charlie Bragg

Tom

Paul

Gary Fields

David Wilder

Thomas Wilson

Mr. Tibbel

Conrad Cain (13 episodes)

Samuel Leibowitz

David Norton

Frank McBride

Matthew Kragen

Bill the Breaker

Paul Gebhard

J.T. Neumeyer (5 episodes)

Ted Milner

Jack Meadows

Larry Sullivan

Archie Goodwin (27 episodes)

Director (3 episodes)

Executive Producer (27 episodes)

Isaac Alder

Rod Smolla

Marshall Thompson

Archie Goodwin

Colonel William Kent

Frankie

Aldrich Ames

Self (1 episode)

Sam Ellis / John Larkin

Raymond Blossom

Director

Lee Egan

Martin Geldhart

Richard Loving

Willie Conway

Martin Ryan

Charlie

F. Scott Fitzgerald

Thad Beaumont / George Stark

Peter Derns

(voice) (1 episode)

Tom (Windows)

Self - Performer (1 episode)

Al Reilly

Dimitri Sanin

Donnie 'Cake'

Juggler at the Fair (uncredited)

Jack

Mike Shea / Elmo Barnett

Director (1 episode)

Jimmy Lynch

Christopher Boyce

Self - Cameo (uncredited) (1 episode)

Dr. Stanley Shephard

Daniel Isaacson

Self - Nominee (1 episode)

Cadet Major Brian Moreland

Donald Branch Booth

John Mullen

Jim

Conrad Jarrett

Paul Winters (1 episode)

Paul Winters

Cadet

Derek Clayton

Jason Kramer

Tommy Callahan

Art