After the United States entered World War I, Donovan was sent to Europe with the American Expeditionary Forces (AEF). As a major, he commanded 1st Battalion of the 69th New York Infantry Regiment in the 45th Infantry Division. Donovan took part in the September 1918 Saint Mihiel offensive. Then a lieutenant colonel, he was wounded but refused evacuation and stayed to lead his men. His actions brought him the Medal of Honor and the nickname of "Wild Bill."
After the war, Donovan returned to Buffalo to practice law. From 1924 to 1929, he was an assistant U.S. attorney general. He ran unsuccessfully for state political office and in 1929 moved to New York City. Much interested in international affairs, Donovan undertook several overseas missions for the Rockefeller Foundation and the Franklin D. Roosevelt administration. Donovan tried to convince Roosevelt and others that the United States needed an intelligence-gathering organization similar to that run by the British. His efforts finally led to his appointment in July 1941 as head of the Office of Coordinator of Information, which after the Japanese attack on Pearl Harbor became the Office of Strategic Services (OSS). It gathered intelligence, conducted propaganda and sabotage, and assisted partisans.
After World War II, Donovan lobbied President Harry S Truman to set up a permanent intelligence organization. Truman initially rejected this step, but the coming of the Cold War led in 1947 to the formation of the Central Intelligence Agency, loosely modeled on the OSS. Donovan's hope of heading the CIA was not realized, although he briefly returned to government service as ambassador to Thailand during 1953 and 1954. Donovan died on 8 February 1959 at Walter Reed Army Medical Center, Washington, D.C.
Cave Brown, Anthony. The Last Hero: Wild Bill Donovan. New York: Times Books, 1982.; Dunlop, Richard. Donovan, America's Master Spy. Chicago: Rand McNally, 1982.; Ford, Corey. Donovan of OSS. Boston: Little, Brown, 1970.; Troy, Thomas F. Wild Bill and Intrepid: Donovan, Stephenson, and the Origin of CIA. New Haven, CT: Yale University Press, 1996.