Nothing is known of the life of the criminal would become known as Mr. Paradox prior to his appearance in Gotham in 1949,  His appearance coincided with a radio program called the Paradox Man on Alan Scott's WXYZ radio programming.  The 15 minutes of brain teasers had fallen out of favor and Scott, seeking to keep the Paradox Man (real name: Clay Chalmers) employed, reached to industrialist C. K. Nevins as a potential sponsor.  Nevins was not impressed however and Chalmers was let go.  Fearing the despondent Paradox Man might do something drastic, Scott has his Man Friday, Doiby DIckles, follow him home.

Lost in his own thoughts, Dickles loses track of Chalmers right outside one of Nevin's facilities and fearing Chalmers is seeking revenge for not sponsoring his show, rushes inside to save Nevins.  When he does he is confront by an odd situation: The entire staff appears to be asleep on their feet.  While he sputters in disbelief, he confronted by an oddly attired criminal calling himself Mr. Paradox, who directs his men to bind Doiby in his cab while they clean out the vault.  This proves unwise as Doiby is able to signal Green Lantern with a rocket flare installed in the cab.  Arriving quickly, Green Lantern proves unable to catch up with a fleeing Paradox, a puzzle not unlike posed by Chalmers in his last broadcast.  The hero begins to suspect Chalmers has used his failure at WXYZ to turn to crime.

Racing back to the studio, Green Lantern looks up Chalmers address and when he and Doiby find it, Mr. Paradox and his gang are waiting.  After a melee, Lantern is taken down by gas hidden in Mr. Paradox jeweled staff and he and Doiby are bound as prisoners.  To make an example of them, Paradox plots unusual deaths by imprisoning them in glass baubles that are bounced around a fountain. A machine gun is set up to mimic a shooting gallery and the gang departs.  Green Lantern's will power is still sufficient to free he and Doiby and the take off in pursuit of Mr. Paradox.

Following tracks leading to a rail yard, the heroes hide in a box car owned by C.K. Nevin, Inc.  As the criminal break in, they burst forth and caught by surprise, the criminals are overcome.  While Doiby expects to unmask Chalmers, Green Lantern has already deduced that Mr. Paradox is actually Nevins, robbing himself to collect insurance money.  Chalmers, as it turns out, has gone home to Iowa and a normal happy life.  Nevins is turned over to the authorities (Green Lantern #38).

The further activities of Mr. Paradox are unknown.