Tim Considine

~ as ~

Frank Hardy

Tommy Kirk

~ as ~

Joe Hardy

Russ Conway

~ as ~

Fenton Hardy

Sarah Selby

~ as ~

Aunt Gertrude Hardy

Carole Ann Campbell

~ as ~

Iola Morton

Florenz Ames

~ as ~

Silas Applegate

Robert Foulk

~ as ~

Jackley the Plumber

Donald MacDonald

~ as ~

Perry Robinson

Arthur Shields

~ as ~

Boles

Andy Clyde

~ as ~

Lacey