Nimitz?
Fleet Admiral Ernest J. King. King was the United States Navy’s second most senior officer in World War II after Fleet Admiral William D. Leahy, who served as Chief of Staff to the Commander in Chief.
King was one spare no nonsense bad ass. Roosevelt supposedly said that he had heard that King shaved with a blowtorch. King said, “When they get in trouble, they send for the sons-of-bitches.”
King was our third Five Star officer after Fleet Admiral Leahy and General Marshall. List by seniority:
Fleet Admiral William D. Leahy 15 December 1944
General of the Army George Marshall 16 December 1944
Fleet Admiral Ernest King 17 December 1944
General of the Army Douglas MacArthur 18 December 1944
Fleet Admiral Chester W. Nimitz 19 December 1944
General of the Army Dwight D. Eisenhower 20 December 1944
General of the Army & Air Force Henry H. Arnold 21 December 1944 & 7 May 1949
Fleet Admiral William Halsey, Jr. 11 December 1945
General of the Army Omar Bradley 20 September 1950
General of the Armies George Washington 4 July 1976, with an effective appointment date of 4 July 1776
Before the five-star ranks were established in 1944, two officers had previously been promoted from their four-star ranks to the superior and unique ranks of Admiral of the Navy and General of the Armies: Admiral George Dewey (appointment 1903 retroactive to 1899, died 1917) and General John J. Pershing (appointed 1919, died 1948). In 1944 the Navy and Army specified that these officers were considered senior to any officers promoted to the five-star ranks within their services (but it was not clear if they were senior by rank or by seniority due to an earlier date of rank).
Five-star ranks were created in the US military during World War II because of the awkward situation created when some American senior commanders were placed in positions commanding allied officers of higher rank. US officers holding five-star rank never retire; they draw full active duty pay for life. The five-star ranks were retired in 1981 on the death of General of the Army Omar Bradley.
Nine Americans have been promoted to five-star rank, one of them, Henry H. Arnold, in two services (US Army then later in the US Air Force). As part of the bicentennial celebration, George Washington was, 177 years after his death, permanently made senior to all other US generals/admirals, with the title general of the armies, effective on 4 July 1976. The appointment stated he was to have “rank and precedence over all other grades of the Army, past or present.”
Technically one could include General Pershing and Admiral Dewey. But I’m going by the list of promotions commencing in December of 1944. In any event General Eisenhower and MacArthur are down the list a bit.