William Joseph "Wild Bill" Donovan KBE (January 1, 1883 – February 8, 1959) was an American soldier, lawyer, intelligence officer and diplomat. He is best known for serving as the head of the Office of Strategic Services (OSS), the precursor to the Bureau of Intelligence and Research and the Central Intelligence Agency (CIA), during World War II. He is regarded as the founding father of the CIA, and a statue of him stands in the lobby of the CIA headquarters building in Langley, Virginia.

A decorated veteran of World War I, Donovan is believed to be the only person to have been awarded all four of the following prestigious decorations: the Medal of Honor, the Distinguished Service Cross, the Distinguished Service Medal, and the National Security Medal. He is also a recipient of the Silver Star and Purple Heart, as well as decorations from a number of other nations for his service during both World Wars.

Of Irish descent, Donovan was born in Buffalo, New York, to Anna Letitia "Tish" Donovan (née Lennon) and Timothy P. Donovan, both American-born children of Irish immigrants. The Lennons were from Ulster and the Donovans from County Cork. Donovan's grandfather, Timothy O'Donovan Sr., was from the town of Skibbereen; raised by an uncle who was a parish priest, he married Donovan's grandmother Mary Mahoney, who belonged to a propertied family of substantial means that disapproved of him. They first moved to Canada and then to Buffalo, where they dropped the "O" from their name. Donovan's father, born in 1858, worked as the superintendent of a Buffalo railroad yard, as secretary for Holy Cross Cemetery, and attempted to engage in a political career with little success.

Donovan was born on New Year's Day in 1883. (Named William, he chose his middle name, Joseph, at the time of his confirmation.) He had two younger brothers and two younger sisters who survived into adulthood and several additional younger siblings who died in infancy or childhood. "From Anna's side of the family came style and etiquette and the dreams of poets," Donovan's biographer, Douglas Waller, wrote. "From Tim came toughness and duty and honor to country and clan." Donovan attended St. Joseph's Collegiate Institute, a Catholic institution at which he played football, acted in plays, and won an award for oratory. He went on to Niagara University, a Catholic university and seminary where he undertook a pre-law major. Considering the priesthood, he ultimately decided "he wasn't good enough to be a priest," although he did win another oratorical contest, this time with a speech warning of corrupt, anti-Christian forces that threatened the United States.

With the expectation of studying law, Donovan eventually transferred to Columbia University, where he looked beyond "Catholic dogma" and attended Protestant and Jewish worship services to decide whether he wanted to change religions. He joined the Phi Kappa Psi fraternity, rowed on varsity crew, again won a prize for oratory, was a campus football hero, and was voted the "most modest" and one of the "handsomest" members of the graduating class of 1905.^{[citation needed]}

After earning his bachelor of arts, Donovan spent two years at Columbia Law School, where he was a classmate of Franklin D. Roosevelt, and studied under Harlan Fiske Stone. Returning to Buffalo, he joined the respected law firm of Love & Keating in 1909 and, two years later, opened his own Buffalo firm in partnership with a Columbia classmate, Bradley Goodyear. In 1914, their firm merged with another, becoming Goodyear & O'Brien. In 1912, Donovan helped form, and became the leader of, a troop of cavalry of the New York National Guard. This unit was mobilized in 1916 and served on the U.S.–Mexico border during the American government's campaign against Pancho Villa. He studied military strategy and combat tactics. He also took acting courses in New York City from a stage star of the day, Eleanor Robson. In 1914, he married Ruth Rumsey, a Buffalo heiress who had attended Rosemary Hall.

In 1916, Donovan spent several months in Berlin on behalf of the Rockefeller Foundation, seeking to persuade the governments of Britain and Germany to allow the shipment of food and clothing into Belgium, Serbia, and Poland. In July of that year, at the behest of the State Department, he returned to the U.S. and took his cavalry troop to the Texas border to join Brigadier General John J. Pershing's army in the hunt for Pancho Villa. Promoted to major in the field, he returned to Buffalo, then joined the 69th Regiment, also known as the "Fighting Irish Regiment." This was the same 69th of Civil War fame, later called the 165th, which was training for America's expected entry into World War I, and which became part of the 42nd Division, also known as the "Rainbow Division." Douglas MacArthur was the 42nd Division's chief of staff. Donovan's son David was born in 1915, and a daughter, Patricia, was born in 1917. (Patricia died in an accident in 1940.)

During World War I, Major Donovan led the 1st Battalion, 165th Infantry of the 42nd Division. Serving in France, he suffered a shrapnel wound in one leg and was almost blinded by gas. After performing a rescue under fire, he was offered the Croix de Guerre, but turned it down because a Jewish soldier who had taken part in the rescue had not also been awarded the honor. After that insult had been corrected, Donovan accepted the distinction. He was awarded the Distinguished Service Cross for leading an assault during the Aisne-Marne campaign, in which hundreds of members of his regiment died, including his acting adjutant, the poet Joyce Kilmer. The 1940 James Cagney movie, The Fighting 69th, dramatised the events of this battle and the 69th Infantry Regiment's role in it.