- Donald Briggs
- Frank Merriwell
- Jean Rogers
- Elsie Belwood
- John 'Dusty' King
- Bruce Browning
- Carla Laemmle
- Carla Rogers
- House Peters Jr.
- House Peters
- Herschel Mayall Jr.
- 'Hersh' Mayall
- Wallace Reid Jr.
- Wally Reid
- Edward Arnold Jr.
- Eddie Arnold
- Bryant Washburn Jr.
- Bryant Washburn
- Allan Hersholt
- Allen Hersholt
- Carlyle Blackwell Jr.
- Carlyle Blackwell
- Peter Gowland
- Peter Gowland
- Sumner Getchell
- Harry
- William P. Carleton
- Charles Merriwell [Chs.10-12]
- Ben Hewlett
- Daggett
- Ella Ethridge
- Mrs. Mary Merriwell [Chs. 2, 10-12]
- Walter Law
- Murray Belwood [Chs. 4-9]
- Jack Donovan
- Coach Harding [Chs. 1-2, 11-12]
- Al Bridge
- Black - Henchman
- Sam McDaniel
- Jeff [Chs. 2, 10-12]
- King Baggot
- Chemistry Professor
- Clyde Beatty
- Lion Tamer
- Chief John Big Tree
- Indian John
- Lynton Brent
- Helpful Driver
- Viola Callahan
- Mrs. McLaw
- Edmund Cobb
- Pete
- Jim Corey
- Bill / Stalking Indian (uncredited)
- Richard Cramer
- Road Crew Foreman
- Joseph De Grasse
- Dr. Cummings
- William Desmond
- Captain of the 'Viking'
- Al Ferguson
- Big Tom
- Billy Franey
- Barbecue Cook
- M.J. Frankovich
- Baseball Game Announcer
- Chester Gan
- Lumber Camp Cook
- June Gittelson
- Dance Party Guest
- Frank Hagney
- Slout
- Jack Hall
- Theater Doorman
- Millard 'Dixie' Howell
- Football Player
- Dickie Jones
- Jimmy McLaw
- Eddie Kane
- Man in Audience
- David Klatzkin
- Dave
- Isabel La Mal
- Mrs. Belwood
- Bruce Lane
- Yacht Captain
- Charles Lane
- Man in Front Row
- Nick Lukats
- Second Mate of the 'Viking' [Chs. 4-5]
- Philo McCullough
- Berger
- Monte Montague
- Monte
- Carlos Montalbán
- Rurale Captain
- Charles Murphy
- Yacht Crewman
- Dave O'Brien
- George Baldwin
- Artie Ortego
- Indian
- Bud Osborne
- Gorman
- Anita Page
- Trapeze Artist
- Rain-in-the-Face
- Chief Tonaka
- Fred Sumner
- Prof. Baldwin
- Max Wagner
- Pug O'Leary
- Robert Walker
- Lang
- Dick Wessel
- Joe
- Slim Whitaker
- Nolan
- Bert Young
- Judd
