Supervising the trial of an experimental gamma bomb that he designed for the U.S. Defense Department at a nuclear research facility in New Mexico, Bruce selflessly rushed to the rescue of an ignorant teenager who had wandered onto the testing field as the countdown ticked inexorably toward zero. After shoving young Rick Jones to safety in a nearby ditch, Bruce was struck full-force by the bomb blast. He survived, but was irradiated by the deadly gamma energy.
At first, Banner would transform into the brutish gray Hulk only at sunset, and revert to human form at dawn. Eventually, his changes into the childlike green Hulk came to be triggered by the release of adrenaline when he was intensely excited, no matter what time of day. The green Hulk possesses little of Banner’s memory and intelligence, and is easily enraged; making him a menace to society.
Since Banner’s initial transformation into the Hulk, military forces commanded by the implacable General Thaddeus “Thunderbolt” Ross – Bruce’s one-time benefactor – have hunted him continually. Hulk continued to make more enemies within the military such as Major Glenn Talbot as he and Bruce constantly competed for the affections of Ross’ daughter, Betty.
For a short time, Banner successfully treated his condition with radiation and was able to maintain enough of his own personality when he became the Hulk to control himself in that form. Subsequently, he earned the government’s favor by destroying the alien Metal Master and received a presidential pardon.
More on Marvel.com: http://marvel.com/universe/Hulk_(Bruce_Banner)#ixzz26sdMT77C