Greedo thought himself a bounty hunter. He confronted Han Solo in the Mos Eisley Cantina on Tatooine thinking to kill him and bring him to Jabba the Hutt but was shot before he could try anything.
Greedo is a bounty hunter who often works with the gangster Jabba the Hutt. His last job was to confront Han Solo about the cargo of spice he dumped. Unfortunately for Greedo, Han Solo is rarely caught off guard, and Greedo should have shot first.
Born on Tatooine, Greedo spent his days with Anakin Skywalker when they were both only children. Even at a young age Greedo had a bit of a temper and was jealous of what Skywalker could achieve especially after Skywalker won his freedom in a podrace. With such few options on Tatooine for any type of future, Greedo became a bounty hunter and worked mainly for Jabba the Hutt.
Years later Greedo would get a contract for Han Solo to either secure the money he owed Jabba or to kill him and take whatever Solo had with him. Greedo caught up with Han in the Mos Eisley Cantina just after Solo had gotten a escort job that would give him enough credits to pay off Jabba. After trying to get a bride from Solo and pushing him too far Greedo was prepared to shoot Han but Solo gets the draw on him and kills Greedo.
When Star Wars: A New Hope was originally released the scene in which Greedo confronts Han, Han the only one who shoots. It wasn't until the 1997 re-release of A New Hope that adds Greedo taking a shot a split second after Han shoots him, missing Han entirely. George Lucas said this was to make Han Solo less of a ruthless killer. It wasn't until 2004 DVD version that a third alteration was made in which Greedo now shoots at Han first, Han's head is digitally moved like he is dodging the shot, and Han shoots and kills Greedo. Lucas claimed this was to add to Han's image, that he isn't a ruthless killer but is highly skilled and can dodge lasers.
Greedo is not the brightest bounty hunter but was respected by his fellows. Despite his lack of intelligence, and an affinity to jump to anger, Greedo was still a good at his job. His success led to an over confidence in his abilities which is probably led to his death at the hands of Han Solo.