He founded Metaweb but unless I wasn't paying attention he doesn't have a PhD. He's the same age as me so his academic career was in the 80's. jg isn't a big time AI guy but he is very smart and he's been deeply involved with AI projects for at least the last decade.
KG is not what most people think of as AI. It's more of a very large triple database with some confidence metrics than anything like what would pass for machine intelligence today. It's not even in the same org at Google.