Tom Brown
'Smilin' Jack' Martin
Marjorie Lord
Janet Thompson
Rose Hobart
Trudy Muller, aka Fraulein von Teufel
Keye Luke
Captain Wing
Edgar Barrier
Tommy Thompson
Cyril Delevanti
Mah Ling / Han Po, his double
Philip Ahn
Wu Tan
Turhan Bey
Kageyama [Chs. 1-5, 12-13]
Sidney Toler
General Kai Ling [Chs. 1-5, 13]
Jay Novello
Kushimi, infiltrator [Chs. 1-3, 12-13]
Nigel De Brulier
The Lo-San [Chs. 2-3, 12-13]
Edward Keane
Hon. George Hill [Chs. 8-12]
William Forrest
Secretary of Internal Affairs [Chs. 8-12]
Stanley Blystone
Capt. Hardigan [Chs. 5-6]
Herbert Heyes
Sir Cedric [Chs. 5-7]
James Craven
Commissioner Robert George Hardy [Chs. 5-7]
Alex Havier
Sanson, phoney waiter [Chs. 6-7]
Paul Bryar
Herr Bauer [Chs. 6-7]
Norma Drury
Frau Bauer [Chs. 6-7]
Grace Cunard
Second German Woman Spy [Chs. 6-7]
David Hoffman
John O. Blenker [Chs. 9-11]
Edward Peil Sr.
Freighter Captain [Chs. 7-8]
Wheeler Oakman
Freighter Mate [Chs. 7-8]
Harry Strang
Honolulu Detective-in-charge [Chs. 10-12]