Finding Mary Marvel's Good Deed Ledger, the man who became known as Uncle Marvel read its contents and discovered the secrets of the Marvel Family. Taking the book back to Mary, he explained that he was her long lost uncle Dudley from California. When they both said, "Shazam!" Mary and Uncle Dudley were changed. However, unknown to Mary, Dudley had merely slipped out of his outer clothes and was already wearing a costume underneath.

Dudley then set up a business, Shazam Incorporated, naming himself the president, explaining that he would donate the proceeds of money paid for the Marvel's work to a good cause and that it would be a non-profit making venture. Mary soon realised he was a fraud when he said, "Shazam!" and did not change. But none of the Marvel Family said anything and let him continue his charade.

Uncle Marvel often begged off when he was supposed to fly by claiming he had "Shazam-bago." He once used a collapsable rocket motor - his own invention - to fly, but it didn't work properly and it was soon abandoned. It appears that Dudley is his last name, as he has a niece called Mary Dudley (Freckles). Although she sometimes wore a Mary Marvel costume and called herself Freckles Marvel, she never pretended to have any Shazam powers and is not regarded as part of the Marvel Family.