Hart was superintendent at the USNA (1931-34) and in June 1939, he was made a full admiral and given command of the US Asiatic Fleet.
In January 1942, Hart was appointed Naval Commander of ABDA. He directed a couple of operations off the Dutch East Indies but took early retirement from the US Navy in June1942. However he was later recalled to head the Naval Board.
After the war Hart went into politics and was elected as US Senator for Connecticut in 1945. Thomas Hart died on 4th July, 1971.