Jack Armstrong

John Hart

Jack Armstrong

Rosemary La Planche

Betty Fairfield

Claire James

Princess Alura [Chs. 3-6, 9-11, 15]

Joe Brown Jr.

Billy Fairfield (as Joe Brown)

Pierre Watkin

Uncle Jim Fairfield

Wheeler Oakman

Prof. Hobart Zorn

Jack Ingram

Henchman Blair

Eddie Parker

Henchman Slade