- Author:
- Sir Arthur Conan Doyle
- Author:
- William Gillette
- Radio adaptation and production:
- Raymond Raikes
- Dr. John H. Watson (late Indian Army):
- Norman Shelley
- Billy, the page-boy:
- Jonathan Field
- Sherlock Holmes:
- Carleton Hobbs
- Professor Robert Moriarty:
- Frederick Valk
- John Forman:
- Allan Jeayes
- James Larrabee:
- Valentine Dyall
- Madge Larrabee:
- Catherine Salkeld
- Alice Faulkner:
- Sarah Leigh
- Certain members of Moriarty's gang - 'Lightfoot' McTague:
- Tony Quinn
- Certain members of Moriarty's gang - Thomas Leary:
- Michael O'Halloran
- Certain members of Moriarty's gang - Jim Craigin:
- Wyndham Milligan
- Certain members of Moriarty's gang - Alfred Bassick:
- Norman Claridge
- Parsons, servant to Dr Watson:
- John Cazabon
- Sir Edward Leighton:
- William Fox
- Count von Stalburg:
- Victor Fairley