"Han Solo was going to marry Leia, and you look back and say, 'Should he be a cold-blooded killer?'" the filmmaker said in an interview with The Washington Post (via Entertainment Weekly). "Because I was thinking mythologically — should he be a cowboy, should he be John Wayne? And I said, 'Yeah, he should be John Wayne.' And when you're John Wayne, you don't shoot people [first] — you let them have the first shot. It's a mythological reality that we hope our society pays attention to."
The scene takes place at the Mos Eisley cantina, where the lizard-like Greedo corners Solo and forces him to sit down at gunpoint. The pilot claims he has the money to pay the bounty hunter's employer (Jabba the Hutt), and Greedo asks for the money for himself to "forget" he saw him. As Solo says he doesn't have the money with him, the camera focuses on his hand grabbing his gun. Greedo says he's run out of patience and looks forward to killing him, to which our hero says, "I'll bet you have," at which point the versions of the film differ.
The original 1977 cut shows a cloudy explosion and Greedo collapsing. The scene has been altered several times since the 1997 special edition but all of the later versions show Greedo's gun missing Solo before Solo returns fire.
In 2012, Lucas had suggested that Greedo had always shot first but that it was obscured by the way he'd framed the shot. "It had been done in all close-ups and it was confusing about who did what to whom," he told The Hollywood Reporter. "I put a little wider shot in there that made it clear that Greedo is the one who shot first, but everyone wanted to think that Han shot first, because they wanted to think that he actually just gunned him down."
Widespread fan speculation has suggested that the original script for the movie conclusively showed that Solo shot first. The Washington Post interview marks the first time Lucas has explained his rationale.
Harrison Ford, meanwhile, has voiced his stance on who shot first: "I don't know and I don't care," he told Reddit users in a 2014 AMA.