Bruce Banner's childhood dream was to be like Captain America, a skinny youth transformed into an athletic hero. Graduating university two years early, he sought to reproduce the lost super-soldier serum, working for the government under S.H.I.E.L.D.'s General Ross. He became head of the Pittsburgh-based Super-Soldier Program, got engaged to Ross' daughter, Betty, and developed a rivalry with fellow scientist Hank Pym. Rumors persisted that he conducted trials on civilians during departmental lean years; he certainly tested formula on himself more than once. The last test transformed Banner into an intellectually limited, instinct-driven, green-skinned behemoth. Dubbed the Hulk and pursued by Ross' troops, Banner rampaged across the country, briefly reverting to human form during an encounter with Spider-Man.

Eventually restored to human form, and testing negative for Hulk cells, Banner returned to work. When new S.H.I.E.L.D. head Nick Fury expanded the Super-Soldier Program, Banner was demoted to Pym's second-in-command . Dumped and belittled by Betty, and jealous of Pym's successful projects, Banner felt increasingly insecure as he failed to make further progress with his serum. The discovery of the original Captain America, alive and well, provided new data but no breakthrough. Overhearing his colleagues mocking him, Banner cracked; he re-injected himself with his Hulk serum, now laced with Captain America's blood. Becoming a more brutal, gray-skinned Hulk, he slew 852 people on a murderous rampage through Manhattan, trying to reach Betty before the Ultimates finally subdued him. Banner was sealed away in special high-security prison quarters beneath the Triskelion and kept partially sedated to prevent another transformation. His connection to the Hulk was concealed from the public. The Hulk intrabodies had now bonded with his DNA, leaving an apparently permanent risk of transformation. Betty reconciled with him, seemingly aroused by his darker side; Banner meanwhile worked on curing himself, to no avail. When the extraterrestrial Chitauri threatened Earth, Banner was deliberately provoked into transforming, and battled against the invaders before Hawkeye recaptured him using a tranquillizer arrow.

After Hulk's identity was leaked to the press, a penitent Banner was tried for mass murder and sentenced to death, despite competent defense by Matt Murdock. Banner was sedated and left aboard the decommissioned U.S.S. Constellation to die in a nuclear explosion., A sympathetic Pym reduced Banner's dosage and Bruce awoke, transforming seconds before the explosion. Bruce Banner now wanders a world that thinks him dead, trying to find a way to control the raging monster that dwells within him.