/Film have done a nice job telling us who exactly Hector Hammond is (which is lucky since I know nothing!):
He’s based more on the Geoff Johns GL stories than the early comic appearances, and was said to be “the pathologist son of a senator who is seen as a disappointment in his father’s eyes.”
Hammond comes into contact with the radioactive meteorite in the crashed spacecraft of Abin Sur, the alien who leads Hal Jordan to becoming Green Lantern. The radiation gives Hammond psychic powers but also deforms him. His head is enlarged and, in earlier versions of the comic character, he is paralyzed.
Green Lantern is set for release summer 2011 so a while to wait yet….