Manfred 'Doc' Montague
Johnny Byrne (uncredited)
Phineas King (1 episode)
Adm. Moffett
SS Henrietta Engineer
David Chase (36 episodes)
Gowrie Twin (uncredited)
H.C. Borden
Steven Blaine
Specs Green
Mr. Gregory / Lane Talbot
William Warner
Ralph McCormick
Cory Williams
Himself
Dr. John Mandre
Harry Curtis
Captain Rockcliffe 'Lucky Rocky' Ames
Dan McLean
Duke Sheldon
Danny Driscoll / John Vincent / George Atwater
Adam Farradene
Chris Faulkner
Bill Hastings
Mark Peters
Perry Warner
John Dodge
Himself
Capt. McCarey
Inspector Barrabal
Kenneth Stevens
Christopher Cross
Philip Trent
Hank Gilman
Harwood
Philo Vance
Sir Everard Dominey / Baron Leopold von Ragostein
Thomas Ignatius 'Tom' Fletcher
King Solomon
Capt. Karl Torok
John Francis Dugan
T.N. Thompson / Mr. Dynamite
Roger Blackwood
Shocker Dugan
Toby Warren
Phillip "Gift of Gab" Gabney
Three-Time
Inspector Dyke
Kenneth Lane
Dr. Wayne Talbot
Casey McCarthy
Brains Stanley aka Roger Winthrop
Harry Quirt
'Gabby' Denton
Russell Kirk
Chandu / Frank Chandler
William J. Burton
Jack Craigen
Sergeant Mickey Dunn
Chatrand
Monty Greer
Sergeant Harry Quirt
Sergeant Quirt
Roger Fallon
Chuck Long
Jim B. Murdock
Sir John Lasher / Dakin Barrolles
David Cressonn
Louis Beretti
Jerry Flanagan
Robert Collings
Sgt. Harry Quirt
Minstrel Show Performer
Harvey Manning
Herbert Littell Dodsworth
Sergeant Mickey Dunn
Geoffrey Sherwood
Babe Stewart
Mile-Away Barry
Stanley Gordon
Pete Clark
Hap Hurley
Slim Paris
1st Sgt. Harry Quirt
Graham
Leonid Petroff
Ricardo Madons
Archibald Carlyle
Daniel Gilchirst
Tom Conway
Richard March
Lord Tancred
Holden, Cyril Gordon
George Tevis
Kirk Rainnsford
Dan Maitland / Anisty
William Trumbull
Prince Kaloney
Jack Carroll
Don John
Norman Arleigh
Capt. Decatur
Bob Rutherford
Nick Carter
Nick Carter
Nick Carter
Nick Carter
Dixon Grant
Phil Garrison
Paul de Veaux
Nelson Smith
Jim Burke
Gordion / Gordon Turner
Johnny Lister
Robert Milton
Peter Judson
Jean Picard
Captain Lewis Nugent
Charles Conquest