Comic Book Origins: The Incredible Hulk

Bruce Banner had a very unhappy childhood, thanks to his alcoholic father, Dr Brian Banner, that literally hated him. His father tried to create clean cheap nuclear energy but he became worried that his son had been affected by the nuclear radiation. Bruce's heightened intelligence only strengthened his fathers beliefs. Brian was extremely violent, he abused his son and actually murdered his wife, which probably traumatized Bruce.

So yeah, his childhood was unhappy. So unhappy that he actually developed split personality disorder. To make his life worse he was also bullied at school. In fact a bulling incident prompted him to plant a bomb in his school! The bomb didn't work but the school obviously wasn't impressed so he was expelled.

But against all odds he became a respected scientist, with a doctorate in nuclear physics. He began a career with the military and started to develop a Gamma-Ray bomb. While testing this bomb in New Mexico he was forced to leave the bunker and enter the blast range of the bomb to rescue a clueless teenager named Rick Jones who had wandered onto the test site. He was successful in helping Rick but as a result he was exposed to gamma radiation.

At first it appeared Bruce had been unaffected by the gamma rays but at sunset he mutated into what we now call the Hulk, except with grey skin (this was because they had problems with printing grey so his skin colored changed to green a few issues later). That night Hulk was pursued by the army. They had him cornered then suddenly, when the sun rose, he turned back into Bruce Banner. Bruce's transformations into the Hulk later happened because of the release of adrenaline rather than the time of day.

Unfortunately due to his rare condition of turning into a green Goliath whenever he gets ticked off, he began to be continuously hunted by the military forces commanded by General Ross, the father of Betty Ross, the woman who both Hulk and Bruce loved. But Hulk isn't really the bad guy the army thinks he is, in fact he is even one of the founding members of the superhero team, the Avengers! However he left the team shortly before Captain America joined because he learned the others feared his unstable personality.