Don Markstein’s Toonopedia website. Quickly, though, the Fantom is one of the very first non-DC superheroes to appear in comic books (Amazing Mystery Funnies Vol. 2 No. 7, July 1939) after Superman...Fantom was never shown with a secret identity, no origin story, no reason given for doing what he did...lived in a lab under the New York World’s Fair, protected Fairgoers. Later he was renamed Fantoman and earned his own short-lived comic book, but then Centaur went out of business and it was goodbye to the guy. He was probably created by Paul Gustavson, who went on to a prolific career in comics of the forties.
Today I have a story of the Fantom protecting those Fairgoers from a giant robot. And really, that is almost my sole reason for showing it. Historic or not, in my mind the Fantom is secondary to a huge, clanking, stomping, havoc-wreaking mechanical man. Paul Gustavson gets the byline for drawing (and probably writing), and Frank Thomas gets the honors for drawing the dramatic cover.
From Amazing Mystery Funnies Vol. 2 No. 11 (1939):