Rex

Rex King of the Wild Horses

Rin-Tin-Tin Jr.

Rinty

Bob Custer

John Sheldon

Lucile Browne

Alice Ingram

Ben Turpin

Henry

Edmund Cobb

Henchman Jim Luger

Richard Cramer

Frank Nolan

Lafe McKee

Charles Ingram [Chs. 1, 3, 12]

Ernie Adams

Henchman Raymond

Slim Whitaker

Henchman Mack

Richard Alexander

Lewis R. Lou Salters [Ch. 1]

Jack Rockwell

Sheriff [Chs. 1, 7-8, 11-12]

George Chesebro

Henchman Parks [Ch. 1]