Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Fleet Admiral William Daniel Leahy (May 6, 1875 July 20, 1959) was an American naval officer, Governor of Puerto Rico and Ambassador to France. Leahy was appointed as Chief of Staff to President Franklin D. Roosevelt in 1942 and served in that position throughout World War II, and continued under President Harry S. Truman until finally retiring in 1949. Fleet Admiral Leahy was the first U.S. military officer ever to hold a five-star rank in the U.S. Armed Forces.