“CASSIDY PLAYS AN UNDERCOVER GAME!”
Disguising himself as a milquetoast Easterner who writes Western novels, Hoppy enrolls in a dude ranch in order to unmask the murderer of the owner's husband.
William Boyd
Hopalong Cassidy
George 'Gabby' Hayes
Windy Halliday
Russell Hayden
Lucky Jenkins
Charlotte Wynters
Ann Marsh
Jan Clayton
Dorrie Marsh
Robert Fiske
Monte Keller
Kenneth Harlan
John Marsh
Anthony Nace
Steve Dorman
Kathryn Sheldon
Abigail Snodgrass
Maurice Cass
E. Prescott Furbush
Alphonse Ethier
Superintendent
Glenn Strange
Bouncer
Claudia Smith
Mary Rogers
Jack Rockwell
Stage Driver Bill (uncredited)
Buck Bucko
Barfly
Red River
Two-Gun Caballero
The Tulsa Kid
Arizona Trail
Cowboy in the Clouds
Big Jake
China 9, Liberty 37
Abilene Town
Alias John Law
Raiders of Red Gap
Silver Spurs
The Feud of the Trail
The Black Stallion
Shawano
The Red Pony
Old Shatterhand
The Fighting Stallion
West of Texas
Green Grass of Wyoming
Frontier Law
Ramrod
Broken Lance
The Tall Men
Forty Guns
Pardners
Monte Walsh
Day of Reckoning
Appaloosa
Man Without a Star
Tall in the Saddle
Boss Nigger
The Cowboys
Scooby-Doo! Shaggy's Showdown
Go West
Montana Story
McLintock!
Young Guns
A Perfect Pairing
The Man From Snowy River II
