If one wishes to give the most credit for Star Wars I would give it to John Williams. Lucas really lucked out when Spielberg suggested him after he had done so well with Jaws. Probably no movie has been transformed into what it was meant to be by the score than the first Star Wars. There was a news clip years ago which showed a bit of the film without music and with. It was like night and day.
I have a Nephew who told me that if he ever gets to be emperor of some country, he will make the theme to “Star Wars”, his national anthem.
Quite true. Williams’ score for Star Wars was stunning, even if based mostly on Wagner, with a cribbing from Holst’s “Mars” for Darth Vader’s march.