Nothing is known of the criminal who called himself the Mad Hatter prior to his appearance in Gotham City in 1948,  His first recorded activities include a hold-up at an exclusive Gotham City yacht club where Bruce Wayne was in attendance.   After carting off trophies and other loot, the Mad Hatter and gang steal one of the yachts to make an escape.  Quickly changing into Batman, Wayne gives chase with an intrepid photographer - Vicki Vale - in tow.  Leaping from a boat he had commandeered onto the Hatter's vessel, Batman expects an easy captured but his repelled by a gas gun hidden in the criminal's hat.

The following day, the police receive a clue from the Mad Hatter: A woman's riding hat.  Vicki Vale is accompanying a suspecting Bruce Wayne to a equestrian exhibition when the Mad Hatter and his gang ride in on horses.  Admonishing the crowd to hand over the valuables, the thieves get as much as they can before Batman and Robin arrive.  While the Dynamic Duo take down his accomplices, the Hatter takes aim at Robin but Batman on horseback thwarts him and sends the villain reeling.  Once more, the Hatter has disguised weapons in his hat, this time a smoke screen that cover his escape.

The following day, another hat arrives at the police station and Batman picks it up for study.  Finding hay on it, he is clued in to abandoned barn theatre in which the last show was based on Alice in Wonderland.  Suspecting this as a possible hideout for the Hatter and his gang, Batman, Robin and Vicki Vale barge in.   They catch the Hatter off-guard and when Vale snaps a picture, it distracts the villain long enough for Batman to subdue and cart him off to the police (Batman Comics #49).

The latter activities of the Mad Hatter of Earth-Two have not been recorded.