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Fleet Admiral William D. Leahy


A photograph of William D. Leahy later in his career (

Fleet Admiral William Leahy was a major decision maker for the United States military during World War Two, serving as the head of the Joint Chiefs of Staff, and as one of Roosevelt’s and Truman’s closest military advisors.  He also served as Chief of Naval Operations leading up to World War II, and helped expand the navy significantly in the years leading up to the war.

Growing up/Early Career

Leahy was born in 1875 in Hampton, Iowa, the son of a Civil War veteran. [6]  His family moved to Ashland, Wisconsin for his high school years, and he considered Ashland to be his true home town.  His father had graduated from West Point, so when he graduated high school, he sought an appointment there. There were no appointments available, so he grudgingly went to the Naval Academy instead, a choice he would not regret later in his life.

He graduated 14 out of a class of 47 in 1897.  He saw action in the Spanish-American War as an ensign and in World War I as the captain of an ocean liner turned troop transport.[6]  In 1917 during the proving trials of the brand new battleship USS New Mexico, Leahy gained a reputation for being able to make quick and direct decisions.[3]  When the speed trial commenced on the New Mexico, the ship threw a blade from one of her propellers and the ship reportedly started to shake violently.  Leahy faced a decision to end the trial for a perfectly good reason, or to press onward.  Without hesitation he ordered the test to continue and the ship passed her speed trials.  When Franklin D. Roosevelt was the assistant secretary of the navy, Leahy was a commander serving as Director of Naval Target Practice. The two met and became friends, and maintained a first name relationship up until Roosevelt’s death.[3]

Leahy was appointed Chief of Naval Operations in 1937, and immediately began campaigning for a stronger navy to combat the rise of Japan in the Pacific, as well as to prepare the country for a potential global war.[6]  His efforts resulted in the navy increasing in tonnage by more than twenty percent, and more importantly, significantly increasing its air power.[6]  He also expanded several naval air bases in the Pacific leading up to the war.

The USS Panay foundering in the Yangtze River after an attack from a Japanese Bomber (

World War II on the Horizon

In the years just before World War II, Hitler was ranting about living space for the German people, Mussolini had just conquered Ethiopia, and Japan had just committed to further war in China at the Marco Polo bridge.  In the midst of all this, on December 1, 1937 a Japanese bomber sunk the American gunboat USS Panay while it was anchored in the Yangtze river outside Nanjing.[3]

Leahy, Chief of Naval Operations at the time,  went to the White House and advised President Roosevelt to go to war with Japan.  Leahy was not a man that loved war, but he knew another World War was coming unless something was done about it.  He saw the attack as an opportunity to show the world there was a nation committed to fighting for peace.  He argued that going to war with Japan would stop them from conquering any more territory.  It would also stop Hitler’s and Mussolini’s plans for conquest because it would show them there was someone willing to stand up to them.  His thought was at the moment, war with Japan would have been very favorable for the United States, and they could easily blockade Japan and bring them to peace.  He stated that the United States navy was superior for now, and if the Japanese sailed from harbor to meet them in open combat to break the blockade, they would be destroyed.  He also figured that war with Japan was inevitable, and the balance of power might not be so favorable for the United states in the years to come if Japan decided to build up her forces.[3]

Leahy convinced Roosevelt of his opinion, and was ordered by the president to get his plan for the blockade ready.  Leahy went to work, secretly gathering the fleet and waited every day for the declaration of war that Roosevelt had said was so necessary.  After some time, Leahy was recalled to the White House and Roosevelt talked to him in private.  Roosevelt said that the country was just not “war minded” and he could not declare war on Japan because of it.  In 1936, Roosevelt had won an election with a campaign declaration of “I hate war.”[3]

After Roosevelt had rebuffed his advice, Leahy continued his duties as Chief of Naval Operations and continued to expand America’s naval power.  When he reached the naval retirement age of 64 in 1939, he left the navy to govern Puerto Rico.   However the former secretary of the Navy, now turned President Roosevelt said to him: “Bill, if we have a war, you’re going to be right back here helping me run it.”[10]

Ambassador to France/Fleet Admiral

After Leahy’s retirement, President Roosevelt appointed him the governor of Puerto Rico. [5] While governor, he constructed several military bases and did not intervene in local politics.  Instead, he took the approach of trying to understand the local customs and ways of doing things before intervening.  Eleven days after the war in Europe broke out, he was recalled from his governorship and reinstated to the navy to be put in command of the naval forces in the Caribbean.[3]

After France fell to the Axis less than one year into the war, Leahy was chosen to represent the United States in the newly created Vichy government.  He went into this assignment knowing that the Vichy government was controlled by the Germans and knew that treaties alone would not keep the United States protected in this war, saying: “to expect that modern diplomacy will safeguard the propriety of a nation is to expect too much. … To believe in the efficiency of pacts and treaties to protect us against international brigandage is the dream of visionaries.”[3, pg. 6]  Despite his doubts in modern diplomacy, Leahy did well in his role as ambassador.  He became close with the leader of Vichy France, Marshal Philippe Petain, who reportedly wrote a post war letter to Leahy imploring him to testify on his behalf when Petain was on trial.  Leahy summarily denied Petain’s request.[4]

In May 1942, his wife of 38 years passed away in France and was later buried in Arlington. [4] Not more than two months after her death, and after serving two years in his role as ambassador, Leahy was recalled to the United States by the president himself.  On July 21, 1942  Roosevelt appointed him to a newly created position titled: “Chief of Staff to the Commander in Chief,” or better known today as the Chairman of the Joint Chiefs of Staff.[7,pg 196]  This position is the most senior position in the United States military.  It was now Leahy’s duty to follow all parts of the war and advise Roosevelt on all military strategy. [7]   The advice that Roosevelt had spurned from Leahy in 1937, which had demonstrated Leahy’s foresight and tactical ability, must have played a role in the president’s decision to appoint him his chief war advisor.

During and after the war, Leahy was described as “a deep water sailor unwillingly at a desk post.”[3, pg. 6]  He was a man who wanted to listen to the other side of the argument and was known to be an open minded man who listened to what his subordinates had to say before making his decisions.  In 1944, when Allied forces were thrusting towards the heart of Germany and Japan was on the defensive, Roosevelt became authorized by Congress to promote America’s top military leaders to a five star status.  The names on the list include Eisenhower, MacArthur, Marshall, Nimitz, and others, men who are now legends of the time. Out of all these legends, Leahy was the first military leader to be promoted to 5-star status of fleet admiral, and thus was the most senior of the whole list.  Fleet Admiral was the highest rank ever achieved by a naval officer up to that point and Leahy was the top man on the list.[9]  Interestingly, Leahy remains an unsung hero even though throughout the war, Leahy was Roosevelt’s, and Later Truman’s closest military advisor, and influenced many major decisions.

The Yalta Conference/The Atom Bomb

Leahy (directly to the rear of Roosevelt wearing a hat) advised President Roosevelt on military strategy at the Yalta Conference with Josef Stalin and Winston Churchill in attendance (

Nearing the end of the war, when it became clear that Germany would fall, a historic meeting of world leaders took place.  It was called the Yalta conference, and the “big three” world leaders, Stalin, Churchill, and Roosevelt met to discuss the reorganization of Europe and the terms of German surrender.  Leahy was Roosevelt’s aide during this conference.  All three agreed that they would demand Germany’s unconditional surrender.[1]  Furthermore, Stalin agreed to join the war against Japan as long as the territories Japan had taken from Russia were returned and The People’s Republic of Mongolia was preserved.[1]  Only a few weeks after the Yalta conference, Roosevelt died and Truman was appointed president. Leahy took his place as top military advisor to a second president.

Another world-changing event he was involved in was the decision to use the atomic bomb on Japan.  At first, knowing just how much time and money had been sunk into a weapon that he thought had no clear promise of contributing to the war effort, he called the Manhattan Project “the biggest fool thing we have ever done. The atomic bomb will never go off, and I speak as an expert in explosives.”[8,pg 499]  When it became clear the atomic bomb would actually work, he was still vehemently opposed to its use. In his memoirs he talked about the decision Truman faced.  According to Leahy, initially, Truman opposed the idea.[2]  Eventually, Truman was convinced to drop the bomb by being persuaded that it would save hundreds of thousands of American and Japanese lives.  Leahy’s opinion of the weapon was the Atomic bomb would not help the allies win the war against Japan, and that the Japanese were already beaten and ready to surrender because of the naval blockade and effective conventional bombing campaign. [2] Truman chose to ignore his advice and gave the go ahead to drop the two bombs the United States had produced on urban targets in Japan.  Leahy remained bitter about Truman’s decision to drop the bomb long after the war, and thought that the only reason it was dropped was because the scientists wanted to see it tested after the vast sums of money that had been invested in the project.  There may have been some merit to Leahy’s stance, because the Japanese surrendered only after the Soviet Union had invaded their territory, and not just directly because of the bomb.  He records in his book I was There that a scientist from the Manhattan Project once told him that he wished the bomb hadn’t worked, and Leahy agreed with the scientist’s sentiment.[2]  He never changed his opinion about atomic weapons and hated the use of them until his death.

A historical marker commemorating William Leahy in Ashland, Wisconsin (

After WWII

After the war, Leahy served as the head of the joint chiefs of staff for several more years before finally permanently retiring in 1949.  In July 1959 he died and was buried in Arlington National Cemetery.[6] Fleet Admiral William D. Leahy died as a largely unsung hero of World War II,[9] one who had built up the United States Navy before the war, been a governor, ambassador, and top military advisor to two presidents.  He was a man that demanded and deserved respect and was involved in many world-changing events.


Primary Sources

  1. Leahy, William D.(1954) “Notes on the Yalta Conference.” The Wisconsin Magazine of History 38, no. 2: 67-112.
  2. William D. Leahy (1950) “I Was There” New York: Whittlesey House, pp. 440-442
  3. Trohan, W. (1945, Jul 01). Admiral William D. Leahy. Chicago Daily Tribune
  4. Darrah, D. (1942, Apr 28). Laval Pays Call on Adm. Leahy at U.S. Embassy. Chicago Daily Tribune; Apr 28: pp. 5 
  5. Chicago Tribune Press Service (1939, May 13) “President Names Admiral Leahy Island GovernorChicago Daily Tribune; May 13, pp. 8 

Secondary Sources

  1. Naval History and Heritage Command (2016) Fleet Admiral William D. Leahy Seventh Chief of Naval Operations” Web. U.S. Navy 
  2. Emerson, William. (1958)  “Franklin Roosevelt as Commander-in-Chief In World War II.Military Affairs 22, no. 4: 181-207
  3. Louis Morton (1957) The Decision to Use the Atomic Bomb”  Center of Military History, United States Army, pp. 499
  4. Harsch, Joseph (1985) “Biography of World War II’s modest, unsung hero: Admiral Leahy” The Christian Science Monitor, web
  5. Chen, Peter “William Leahy Timeline” World War II Database


For Further Reading: