Fox and Moldoff introduce Simple Simon in Flash 53 (May 1944).
We get introduced to Simon as a child, growing up on the wrong side of the tracks. Simon observes how criminals devise complex schemes, which often wind up causing their downfall.
Simon decides that the way to succeed at crime is to make it as simple and basic as possible, and indeed he manages to get away with a number of thefts before Hawkman gets on his trail. And even that only happens because Hawkman sees him at a few crime scenes.
Hawkgirl is involved in the story, but once again only tangentially. Simon tries to take down Hawkman by crushing his foot with a blowing ball. It’s not a bad idea in general, but pretty useless against a hero who can fly.
Simple Simon returns in a few months.