When did the last living fleet admiral who played a major role in the naval history of World War II as Commander in Chief, United States Pacific Fleet, die?
Fleet admiral (United States):  Although it is a current and authorized rank, no U.S. Navy officer presently holds it, with the last living U.S. Navy fleet admiral being Chester W. Nimitz, who died in 1966. Chester W. Nimitz:  He played a major role in the naval history of World War II as Commander in Chief, United States Pacific Fleet (CinCPac) and Commander in Chief, Pacific Ocean Areas (CinCPOA), commanding Allied air, land, and sea forces during World War II.
1966