He was the highest-ranking U.S. Army officer killed in World War II.
Leslie McNair
Simon Bolivar Buckner
Maurice Rose
Theodore Roosevelt Jr.
Leslie McNair. He was Commanding General of US Army Land Forces when his plane was shot down by friendly fire over France in 1944. Simon Bolivar Buckner, who was junior to McNair by date of rank, was killed by Japanese artillery fire on Okinawa.