- Esther Dale - Ellen the Maid
- Yuki Shimoda - Koto
- Kenneth Haigh - Detective Insp. Harry Roberts
- Jester Hairston - Papa Benjamin
- Marlo Thomas - Susan Baker
- Dianne Foster - Judy Patterson
- Dan Tobin - Ray
- Sam Edwards - Charles Larrimore
- Frank Overton - Bart Hattering
- Adele Mara - Lydia Adler
- Luciana Paluzzi - Madalena
- Richard Chamberlain - Larry Carter
- Mort Sahl - Sam Lynch
- Clancy Cooper - Chief Constable
- Macdonald Carey - Hector Vane
- Rip Torn - Duncan Corey
- Jay C. Flippen - Harry Gans
- Judson Pratt - Lt. Bill Gordon
- Hardie Albright - Willet Goodfield
- Richard Kiel - Master Styx
- Susan Oliver - Edith Landers
- John Craven - Dr. Hilton
- Alan Carney - Burgin
- Herbert Rudley - Max Quinke
- Philip Carey - Darryl Hudson
- Donald Woods - Dr. John Carmody
- Brandon De Wilde - Timothy Branner
- Henry Silva - Toby Wolfe
- Doro Merande - Melba Pennaroyd
- Jo Van Fleet - Mrs. Cissy Hawk
- Oskar Homolka - Pierre Jacquelin
- Tom Poston - Charlie Denham
- Natalie Schafer - Beatrice Graves
- Ursula Andress - Luana
- Alberta Nelson - Marie Browning
- Martita Hunt - Celia Sommerville
- Norma Crane - Nell Le Jean ('Welcome Home')
- Gina Gillespie - Priscilla
- Ann Todd - Sylvia Lawrence
- Leo G. Carroll - Major Downey
- Dick York - Fred Bancroft
- Jackie Joseph - Miss Martin ('Goodbye, Dr. Bliss')
- Robert Douglas - Antony Hugh Swinburne
- Edward Platt - James Weeks
- Patricia Breslin - Dinah Duffay
- Pippa Scott - Marcia Elizabeth Hunter
- Nancy Kelly - Janet Willsom
- Reta Shaw - Celia Hooper Somers
- Jack Carson - Burt Lewis
- Jeanne Bal - Judy Wilson
- Ray Teal - Sheriff Wiley
- Boris Karloff - Self - Host
- Boris Karloff - Dr. Albert Farnham
- Boris Karloff - Clayton Mace
- Boris Karloff - Dr. Thorne
- Boris Karloff - Pop Jenkins / Col. Jackson Beauregard Finchess
- Boris Karloff - Doktor Konrad Markesan
- Torin Thatcher - Jeremy Teal
- Guy Rolfe - Vladimir Vicek
- George Macready - Mr. Smith
- Bert Remsen - First Detective
- Beverly Garland - Ruth Kenton
- Larry Blyden - Ralphie Teal
- Sue Ane Langdon - Queenie de Lyte
- Russ Conway - Lt. Boutaric
- Al Ruscio - Allah El Kazim
- Roberto Contreras - 2nd Guerrilla
- Natalie Trundy - Lily Hanson
- Rhodes Reason - Anthony Page
- John Marley - Dr. Tony Romano
- Jessie Royce Landis - Mrs. Kilburn
- Whitney Blake - Jane Kimball
- Seymour Green - Sir John Herbert
- Stuart Erwin - Uncle Florian
- Jack Mullaney - Fred Forrest
- Judith Evelyn - Mildred Adler Beaumont
- Martin Kosleck - Col. Andre Bertroux
- Bruce Dern - Johnny Norton
- David McLean - Ben T. Willsom
- Adam Williams - Hymie Kralik
- John Qualen - Streetcar Conductor
- Fifi D'Orsay - Toinette
- Rosemary Murphy - Lavinia Sills / Alice Quimby
- Ned Glass - Vince Fennaday
- Beverly Washburn - Lollie Harrod
- Estelle Winwood - Aunt Emily Finchess ('Welcome Home')
- Elizabeth Montgomery - Rosamond Denham
- Carl Benton Reid - Dr. Marcus Graham
- Robin Hughes - Collins ('A Terribly Strange Bed')
- Crahan Denton - Sheriff Buckner
- Vito Scotti - Buddy Welsh
- Otto Kruger - Bert Farrington
- Phil Arnold - Curly
- Berry Kroeger - Paul Mowry
- John Banner - Prof. Martin Vander Hoven
- Gary Clarke - Arthur Smith
- Angela Greene - Mrs. Carlisle
- Argentina Brunetti - Anna Romano
- Larry Pennell - Larry Weeks
- Sue Randall - Kay Salisbury
- Ross Elliott - Charles Merriweather
- Charles McGraw - Sheriff Cliff Wrights
- Barry Gordon - 'Slip-Slip'
- Ramon Novarro - Maestro Giuliano
- John Emery - The Pawnbroker
- Cloris Leachman - Beatrice Stafford
- John Mitchum - Policeman
- Cynthia Pepper - Receptionist
- Richard Carlson - Guy Guthrie
- Russell Johnson - Adam Talmadge
- Henry Corden - Detective Sid Benajain
- John Ireland - Eddie Wilson
- Virginia Christine - Marge
- Joe Maross - Ray Kenton
- Sidney Blackmer - Edward Stapleton
- James Westerfield - Al Matthews
- Gregory Gaye - The President
- Robert Ellenstein - Dr. Brauner
- Gale Robbins - Mary Jerold
- Jim Bannon - The Police Lieutenant
- Frieda Inescort - De Chantenay's Mother
- William Schallert - Prof. John MacFarland ('Friend of the Dead')
- Edgar Buchanan - Doc O'Connor
- Phyllis Thaxter - Ursula Sommerville
- John Fiedler - Herbert Bleake
- Richard Long - Dick Farrington
- Edmon Ryan - Capt. Pete Jago
- Mary Grace Canfield - Ally Rose
- Mary Grace Canfield - Celia Perry
- Reginald Owen - The Hussar ('A Terribly Strange Bed')
- Charles Aidman - George Mikos
- Charles Aidman - Jerry Welch
- Ron Ely - Lt. Mike Hudson
- Virginia Gregg - Edna Leggett
- Howard Morris - Myron Sills / Dr. Wilfred Bliss
- Robert Middleton - Monsieur de Paris
- Robert Middleton - Ohrback
- Abraham Sofaer - Gus Kostopulos
- Abraham Sofaer - Nicolai
- Robert Lansing - Lieutenant Brian Rome
- Scott Marlowe - Julian Boucher
- Richard Anderson - Oliver Judson
- George Mitchell - Doc Mulloy
- George Mitchell - Sheriff Pete Browning
- Donna Douglas - Laura Bellman
- Burt Mustin - The Redcap
- Robert Vaughn - Dr. Frank Cordell
- Hayden Rorke - Dr. Frank
- Paddi Edwards - The Nurse
- Robert Colbert - Capt. Bartolomeo Antonio Fernandez
- Constance Ford - Louise Jenkins
- Constance Ford - Connie Walworth
- Billy Barty - Sam
- Jon Lormer - Undetermined Role (credit only)
- Stanley Adams - Mr. Schwenk
- Frank Silvera - Cesare Romano aka Charlie Roman
- Parley Baer - Fisherman on Mountain
- James Gregory - Howard Yates
- K.T. Stevens - Virginia Grant
- K.T. Stevens - Olive Guthrie
- Robert H. Harris - Jerry Roberts
- Tom Nolan - Hank Hattering
- Tom Nolan - Rennie Harrod
- Glenn Strange - Indian (scenes deleted)
- Victor Sen Yung - Bartender
- Paul Hartman - Uncle Gregory Stafford
- Elizabeth Allen - Liz Talmadge
- Elizabeth Allen - Dorothy Lyndon
- Willis Bouchey - Lt. Farnham
- Werner Klemperer - Mr. Clark
- Hal Baylor - Pete Gogan
- Robert Webber - Arthur Henshaw
- Lloyd Bochner - Prof. Harry Langham
- Patricia Medina - Nadja
- Patricia Medina - Victorine Lafourcade
- Lillian Bronson - Adelaide Leggett
- George Kennedy - John Paterson
- Jack Lambert - Lem Carta
- Philip Ober - Elmer Hooper
- Philip Bourneuf - Dr. Weatherbee
- Ruth Warren - Mrs. Rooney
- John Williams - Sir Guy
- Antoinette Bower - Annette Jacquelin
- Antoinette Bower - Sheila Corbett
- Danielle De Metz - Babette Lamont
- Kasey Rogers - Anthea Jason
- Jack Weston - Edward Dean
- Jack Weston - Maurice Reynard
- Elisha Cook Jr. - Harry Elser
- Bethel Leslie - Gale Hattering
- Bethel Leslie - Ann Merriweather
- Kathleen Crowley - Dr. Lois Walker
- Kevin Hagen - Sgt. Spivak
- Kevin Hagen - Arno Lunt
- Milton Parsons - Butler
- Denver Pyle - Ortho Wheeler
- William Windom - Lou Walters
- Diana Millay - Ellen McKinstry
- Mary Astor - Rose French
- James Seay - Herb Innes
- Peter Leeds - Larry (uncredited)
- Sean McClory - Patrick Galt
- Sean McClory - Sean O'Danagh
- Shepperd Strudwick - Douglas Kilburn
- Jeanne Cooper - Ethel Bankstrom
- Irene Hervey - Mrs. Edith Pettit
- William Allyn - Randy Hagen
- Guy Mitchell - Detective Hazlett
- Anthony Caruso - Johnny Longo
- John Carradine - Jed Carta
- John Carradine - Jason Longfellow
- Joe De Santis - Col. Sangriento
- John Newland - Robertson Moffat (uncredited)
- John Newland - Ellis Corbett
- Frank De Kova - Lieutenant Vincoli
- Warren Oates - Benny
- Warren Oates - Hugo Wheeler
- Oscar Beregi Jr. - Rev. Burkhardt
- Alejandro Rey - Robert Lamont
- Alejandro Rey - Tonio Bellini
- Jody Fair - Helen Weeks
- Howard Freeman - Jared Leggett
- Maurice Dallimore - George Griffith
- Maurice Dallimore - Bokor
- Michael Pate - Shanner ('The Mask of Medusa')
- Clegg Hoyt - Kyle
- Gil Perkins - Eddie
- Gil Perkins - Mechanic
- Vladimir Sokoloff - Papa Glockstein
- Vladimir Sokoloff - The Janitor
- Marion Ross - Kay Forrest
- Will Wright - Constable Tom Walker
- Jocelyn Brando - Myrtle Hooper
- Jocelyn Brando - Emma Snyder
- James Griffith - Ed Brandies
- James Griffith - Victor Harrod
- Tommy Farrell - The Messenger
- Jane Greer - Ann Moffat
- Jack Livesey - Haley Dalloway
- Chubby Johnson - Charlie Pringle
- Frank Albertson - Charles Salisbury
- George Grizzard - Merle Jenkins
- Audrey Dalton - Meg O'Danagh Wheeler
- Audrey Dalton - Norine Burton
- Audrey Dalton - Nesta Roberts
- Anne Seymour - Aunt Hortense Stafford
- Alan Napier - Attorney Pinchot
- Alan Napier - Lawyer Ridgewater
- Alan Napier - Constable Evans
- Hazel Court - Leonie Vicek
- Grandon Rhodes - Judge Pfluger
- Edgar Dearing - The Police Sergeant
- Alan Caillou - Roscoe Burton
- Alan Caillou - Sir Wilfred
- Alan Caillou - Police Superintendent
- Everett Sloane - Lou Adams
- Rachel Ames - Betty Follett
- Booth Colman - Lieutenant Bailey
- Steve Brodie - Sgt. George Dumont
- Terence de Marney - Uncle Julian ('The Extra Passenger')
- Terence de Marney - Amos Wilder
- Alan Baxter - Sergeant Dane
- Alan Baxter - Sheriff Phil Archer
- John Anderson - Jacob Grant
- John Abbott - Kriss Milo ('The Mask of Medusa')
- Iphigenie Castiglioni - Madame Roberti
- Walter Reed - Police Sgt. Burke
- John van Dreelen - Joel Stone
- Mala Powers - Consuelo De La Varra
- Dayton Lummis - Clarence Kramer
- Dayton Lummis - Millard Braystone
- Robert Osterloh - Capt. Greer
- William Shatner - Paul Graves
- William Shatner - Gil Thrasher
- Peter Brocco - Prof. Thibault
- Peter Brocco - Major Domo ('A Terribly Strange Bed')
- Peter Brocco - Padre Herrera
- Peter Brocco - The Assistant Director
- Mildred Dunnock - Miriam Olcott
- Harry Bartell - Mr. Dalquiss
- Eduardo Ciannelli - Gen. De La Varra
- Eduardo Ciannelli - Inspector Le Boude
- Edward Binns - Lt. Giddeon
- Mona Freeman - Sylvia Walsh
- Nan Leslie - Midge Lewis
- Delores Wells - Flo
- Pepe Hern - Lt. Contreras
- William Phipps - Harry Laxer
- Richard Lupino - Simon ('The Extra Passenger')
- Ellen Corby - Mrs. Peele
- Jeanette Nolan - Granny Harrod
- Jeanette Nolan - La Strega
- Edward Andrews - Maynard Thispin
- Edward Andrews - Frank Logan
- Edward Andrews - Miles Tundifer
- Howard McNear - Jack Passasstroy
- Noel Drayton - Superintendent ('The Mask of Medusa')
- Lane Bradford - Boles
- Ronald Howard - Dr. Edward Stone
- Ronald Howard - Martin Gresham
- Ronald Howard - Robert Penrose
- June Kenney - The Girl
- Myrna Fahey - Alice Page
- Henry Jones - Erik Borg
- Henry Jones - Carl Somers
- Bart Patton - Joe
- Harry Ellerbe - Walter Devon
- Fay Bainter - Geraldine Redfern
- Conrad Nagel - Mayor Walker Wylie
- Ken Renard - Jacob Blunt
- David Whorf - Johnny Banner
- Guy Wilkerson - Howard
- Ottola Nesmith - The Zuvembie, Eula Lee Blassenville
- Bernard Fein - I.L. Gluckman
- Bernard Fein - Lester Clyne
- Bernard Fein - Stage Manager
- Sandy Kenyon - Mason
- Victor Buono - Carolik
- Victor Buono - Dr. Van de Velde
- Vaughn Taylor - Uncle Philip Landers
- Vaughn Taylor - Pontifex Tundifer
- Louis Mercier - Monsieur Armand
- Louis Mercier - The Wall Guard
- Henry Daniell - Count Alexander Cagliostro
- Henry Daniell - Pierre Radin
- Henry Daniell - Vicar John Weatherford
- Henry Daniell - Squire Moloch
- Henry Daniell - Dirk Van Prinn
- Reggie Nalder - Gafke
- Reggie Nalder - Andrew Bentley
- Ed Nelson - Brundage
- Ed Nelson - Charlie
- Ed Nelson - Tom Ellison / Daniel Le Jean
- Richard Reeves - Truck Driver (uncredited)
- Richard Reeves - Patrolman
- Richard Reeves - Truck Driver
- Paul Newlan - Sgt. Bernstein
- Paul Newlan - Paul Hawkins
- Paul Newlan - Sheriff Tom Ulysses Willetts
- Paul Newlan - Joe Henshaw
- Walter Burke - Croxton
- Walter Burke - Lucas
- Doris Lloyd - Dame Alice
- Doris Lloyd - Landlady
- Doris Lloyd - Mother Evans
- Doris Lloyd - Mrs. Edith Pringle
- Linda Watkins - Sylvia Slattery
- Linda Watkins - Arabella Foote
- Linda Watkins - Maggie Henshaw
- Mary Tyler Moore - Sherry Smith
- Mary Tyler Moore - Mary Snyder
- Clem Bevans - Obed
- Clem Bevans - The Old Gaffer
- Lin McCarthy - Frank Clyde
- Lin McCarthy - Peter Duncan
- Joyce Bulifant - Jinny Wells
- Jack Gordon - Arab (uncredited)
- Fred Graham - Sgt. Hannigan
- Fred Sherman - Doctor
- J. Pat O'Malley - The Morgue Attendant
- J. Pat O'Malley - Street Singer
- J. Pat O'Malley - First Pub Patron
- Hal Taggart - Spectator at Inquest (uncredited)
- Cyril Delevanti - The Old Man
- Ron Harper - Younger Thug
- Sol Gorss - George Adams
- Eddie Hice - Barfly (uncredited)
- Stuart Randall - Sgt. Crowell
- Stuffy Singer - Art Brinkerhoff
- Olive Sturgess - Evie Bishop
- Isobel Elsom - Mrs. Purdy (uncredited)
- Michael St. Clair - Road Workman
- Dorothy Neumann - Ruthie Carta
- Andrew Prine - Young Lou (uncredited)
- Pat O'Malley - The Butler
- Sam Gilman - Police Lieutenant
- Gloria Blondell - Maggie Radevik
- Pamela Curran - Second Victim
- Pamela Curran - Gloria
- George Ford - Club Patron (uncredited)
- Marjorie Bennett - Mercedes
- Fletcher Markle
- Maxwell Shane
Jay C. Flippen interpreta a Harry Gans en la serie.
Elisha Cook Jr. interpreta a Harry Elser en la serie.
James Griffith interpreta a Victor Harrod en la serie.
John Qualen interpreta a Streetcar Conductor en la serie.
Percy Helton hace el papel de Replaced (credit only).
Vaughn Taylor interpreta a Pontifex Tundifer en la serie.
John Marley hace el papel de Dr. Tony Romano.
Jessie Royce Landis hace el papel de Mrs. Kilburn.
Leo G. Carroll hace el papel de Major Downey.
Philip Ober interpreta a Elmer Hooper en la serie.
Capítulo disponible en las siguientes plataformas:
