Producer Herman Cohen first considered using "ape" actor Steve Calvert, who had worked with Cohen on Bride of the Gorilla (1951) and Bela Lugosi Meets a Brooklyn Gorilla (1952), but Calvert had retired from performing in his gorilla suit. Cohen turned to another renowned "ape" actor George Barrows, but only hired Barrows' gorilla costume, not Barrows himself. The actor Paul Stockman was instead chosen, based primarily on being a good fit for Barrows' costume. Barrows was annoyed when his gorilla costume was returned from England in bad shape.
Dr. Charles Decker:
Margaret, I can't stand hysterics. Especially in the morning.
Margaret, Dr.Decker's assistant is clearly shown as a doll in the wide shots in which Konga takes hold of her. She is only shown as a doll when the camera is not near her face.