Son of Flubber

Fred MacMurray

Professor Ned Brainerd (archive footage)

Keenan Wynn

Alonzo P. Hawk (archive footage)

Tommy Kirk

Biff Hawk (archive footage)

Ed Wynn

A.J. Allen (archive footage)

Leon Ames

President Rufus Daggett (archive footage)

William Demarest

Mr. Hummel (archive footage)

Paul Lynde

Sportscaster (archive footage)

Bob Sweeney

Mr. Harker (archive footage)

Edward Andrews

Defense Secretary (archive footage)

Alan Hewitt

Prosecutor (archive footage)

Byron Foulger

Proprietor (archive footage) (uncredited)

Darby Hinton

Second Hobgoblin (archive footage) (uncredited)

Harvey Korman

Husband in Commercial (archive footage) (uncredited)

Dal McKennon

First Juror (archive footage) (uncredited)

Burt Mustin

First Baliff (archive footage) (uncredited)

J. Pat O'Malley

Sign Painter (archive footage) (uncredited)

Robert Shayne

Assistant to Defense Secretary (archive footage) (uncredited)