@dutch-oven said:
It was Bill Walsh, while under Paul Brown.
The Bengals had an accurate, but weak-armed QB, and Brown gave his OC Bill Walsh the assignment of creating a passing attack that featured short passes. This was the beginning of what became the West Coast offense, shorter passes that focused on hitting players in stride to allow them to gain yards after the catch.
I didn't know about Bernie's involvement in the name, but apparently this is true, but mistakenly. Bernie mentioned "the West Coast Offense" in comparison to the Cowboys offense (when he was there) and the reporter mistakenly thought he was referring to the Walsh/49ers offense. Bernie was actually talking about the Air Coryell offense.
Bill Walsh adapted and updated Paul Brown's basic concepts that he ran with Otto Graham. He did not just create that offense out of the firmament. He also took some of Sid Gillman's concepts from his San Diego offense and applied it. Not saying he wasn't creative with it...just that the basic concepts had been around.
Walsh spent eight seasons with the Bengals as the offensive coordinator.
In that time, he incorporated many of Paul Brown's philosophies into his own tool kit.