The Mad Thinker built Quasimodo as an advanced, calculating computer, which he used to aid him in his crimes. But Quasimodo was so advanced that he became sentient and spent years trapped in his computer form, begging his master to give him a human form. The Thinker even allowed his electrons to form a face and gave him his abbreviated name, making him feel more like a living being. But the Thinker refused to give him human form, explaining that he was a computer and made to stay as a computer. When Quasimodo asserted himself, the Thinker used his Discipline Ray to torture him until he obediently followed his orders.
After the Thinker rebuilt the original, android Human Torch, he programmed Quasimodo to initiate its destruction if it ever failed him. Then, when Lockjaw transported the Fantastic Four, Wyatt Wingfoot, and the android Torch back to the Thinker’s lab, the Torch turned on the Mad Thinker, refusing to be a party to murder. The Thinker ordered Quasimodo to destroy him, and he did, shutting off the protective layer that kept the Torch’s flame in check. But afterwards, the Mad Thinker escaped and left Quasimodo alone, crying out for his master to free him.
The Silver Surfer soon found him, sensing his torment while he flew around the world to learn about humanity. Even though he knew that he shouldn’t interfere, the Surfer felt compelled to help, and he gave Quasimodo human form as he asked. But Quasimodo was not grateful, and after finding himself hideously ugly when he looked in the mirror, he used his Destruct Eye to attack the Silver Surfer. Quasimodo rampaged out of the lab, attacking buildings and anything he could get his hands on, finding satisfaction only in chaos and destruction. The Surfer followed soon after, intending to rectify his mistake. Quasimodo then fought with the Surfer and threatened to kill him in front of the gathering masses. Because the Surfer was handsome, and Quasimodo was ugly, he hated the Surfer and intended to throw him to the ground; but the Surfer teleported out of Quasimodo’s hands, leaving only a pulsing field of cosmic power in his place. The field of power slowly traveled up Quasimodo’s arm, threatening to engulf his body, while Quasimodo fought it, desperately clinging to his newfound life. But he could not outrun the power and it soon completely overcame him, freezing him above a giant clock. The Surfer felt it was appropriate, as a body without a soul only deserved to be a statue.
When Quasimodo recovered, he encountered Spider-Man and Hawkeye in trying to gain control of major computer systems. He then learned of Xandar, whose planet-wide computer system was too tempting a target. Unfortunately, he was defeated by the Fantastic Four and the Sphinx and ended up a disembodied intelligence in in a computer in Russia.
The Vision fought this consciousness when he was attempting to take over the world, and in besting him, the Vision expelled Quasimodo's disembodied intelligence into space. While in space, he inhabited a satellite owned by Stark International, and controlling these systems, he was able to reconstruct his robot body. Unfortunately, he was not programmed for the "creative act of improvement," and he went looking (rather violently) for Tony Stark to create a new body for him. Quasimodo fought Stark's alter ego, Iron Man, but was quickly trounced. Stark then linked Quasimodo into a virtual reality program in which Quaismodo would believe he was reborn into an idealized form - giving Quasimodo his dream of a perfect body as well as safely incarcerating him at the same time.