He returned to send a wave of confusion through the city's business district, where a pitchman's gadget rained real money on a struggling crowd to mask his gang's work. The diversion drew the Star-Spangled Kid and Stripesy, who found that nothing had been stolen save a life-sized picture of a safe door once sold to the Gotham Jewel Collection — taken so that Mr. Gadget might burn its likeness, divert the guards' elevator with a “disappearing door” trick, and crack the real vault with an electro-magnetic indicator. His true prize, though, was a single rare diamond, by which a commandeered broadcast hour and a supersonic radiation device let him strike down a whole listening city; only Stripesy, his ears still full of water from an earlier scrape and tone-deaf besides, was left untouched to rouse the recovering Kid (Star-Spangled Comics #25).

Posing as the gem dealer Facet, he staged the theft of the Star Emerald by appearing to rob himself, and as the bookman Gould he robbed the Gould collection of rare volumes, each sleight meant to convince the police that he could work miracles. The same masquerade had let him fix a flickering light to the Star Rocket Racer's mirror, by which a coded message worked upon Stripesy until he turned, hypnotized, against his own partner. Only by patient counter-suggestion in a cellar did the Kid break the spell, in time to run aground Mr. Gadget's boldest stroke yet — a sham robbery staged before an unwitting crowd at the Wannafeller Foundation, where a million dollars in radium and platinum were to vanish under cover of a fake police demonstration — as the law moved in (Star-Spangled Comics #28).

He surfaced again as “Dr. Dagget,” a curer of shyness, whose timid pupils were sent out to be arrested for staged crimes — a ruse that stripped the district of policemen, screened the robbery of a laboratory-supply house for materials no longer sold to him, and set the stage for the plunder of Mrs. De Trop's society party by means of a powerful vacuum. The Star-Spangled Kid saw through the pattern, and when a chemical in one of his escape traps turned the fleeing doctor a telltale red, Mr. Gadget — who could no more lose himself in a crowd than blend into one — was run down and unmasked (Star-Spangled Comics #43).

Even behind bars he proved a trickier customer than the police allowed, fashioning from a safety pin and scraps of wire a receiving set and a tiny motor, quietly sawing through his cell bars, and directing his gang along a tapped line while a drugged kitchen kept the guards asleep. From his cell he extorted one hundred thousand dollars from a man named Mallard by way of a phonograph rigged to place the call and play his threat, and he prepared a mechanical-arm trap and an unseen plank of transparent plastic for the heroes who came after him. But the Star-Spangled Kid and Stripesy cut themselves free with the phonograph's own emerald-tipped needle, foiled the payoff, and drew away the invisible plank beneath his fleeing men, so that Mr. Gadget was caught at last in a net and returned to the warden who had been asking after him (Star-Spangled Comics #51).

The later history of Mister Gadget on Earth-Two remains unrevealed.