Brig. Gen. William Mitchell was born in Nice, France, on Dec. 29, 1879. He graduated from The George Washington University with a Bachelor of the Arts degree in 1899. He enlisted in the 1st Wisconsin Infantry on May 14, 1898, and served as a private in Company M, until June 8, 1898, when he accepted appointment as second lieutenant, Signal Officer, United States Volunteers. He was promoted to first lieutenant, Signal Officer, United States Volunteers, on January 21, 1899, and was honorably discharged on April 17, 1899. He was again appointed a second lieutenant, Signal Officer, Volunteers, on April 18, 1899; was promoted to first lieutenant, Volunteers, on June 8, 1900; and was honorably discharged on April 26, 1901 in order to accept a commission in the Regular Army. During this period, he served at various stations in the United States, and in November, 1898 he was ordered to Havana, Cuba, where he was serving at the time he accepted appointment as first lieutenant, Signal Corps, Regular Army, on April 27, 1901.

Brig. Gen. Mitchell, upon being commissioned in the Regular Army, returned to the United States in April, 1901, and was stationed at Fort Myer, Virginia, to August 4, 1901, when he was ordered to Alaska. While in Alaska, he served at Fort Egbert to September 1901; at Fort St. Michael to October 1901; and at Skagway and Eagle City, in connection with the constructing of a military telegraph line, to June, 1903. He returned to the United States in July 1903, and served as Signal Officer, Department of Colorado, Denver, Colorado, to September 1903. He was on duty with Company B, Signal Corps, West Point, Kentucky, to February 1904; and then returned to Denver for duty as Department Signal Officer, remaining there until June 1904. He commanded the post of Fort Myer, Virginia, to September 1904; and Company A, Signal Corps, Fort Leavenworth, Kansas, to September 1906.

Brig. Gen. Mitchell was ordered to Havana, Cuba in September 1906, to serve as Chief Signal Officer until July 23, 1907. When he returned to the United States in July 1907, he attended the Army School of the Line at Fort Leavenworth, Kansas, completing the course as a distinguished graduate in June, 1908. He then attended the Army Staff College, Fort Leavenworth, from which he graduated on July 25, 1909.

Brig. Gen. Mitchell was ordered to the Philippine Islands in July 1909, and upon his arrival was assigned to duty as Chief Signal Officer, Department of Luzon to March 10 1910; and commanded Company L, Signal Corps, at Fort William McKinley to August 14, 1911. Upon his return to the United States, he commanded Company I, Signal Corps, at Fort D. A. Russell (now Fort Francis E. Warren), Wyoming, to September 6, 1912; and then served at Fort Bliss, Texas, to January 30, 1913. He served on the War Department General Staff from February 14, 1913 to June, 1916; and with the Aviation Section, Signal Corps, to March, 1917.

Brig. Gen. Mitchell sailed for France in March 1917, and served as Military Observer and Aviation Officer, Headquarters, American Expeditionary Forces, Paris, to August 25, 1917; as Chief of Air Service, Zone of the Advance to June 25, 1918; as Chief of Service, First Brigade, to July 30, 1918; as Chief of Air Service, 1st Army, American Expeditionary Forces, to October 25, 1918; and as Chief of Air Service, Group of Armies, to November 11, 1918. After the signing of the Armistice, he served as Chief of Air Service, 3rd Army, until he was ordered home in February 1919.

When he returned to the United States on February 28, 1919, he was detailed as Director, Military Aeronautics and Chief, Training and Operations Group, Office, Director of Air Service, Washington, D.C., to April 27, 1921. He was appointed Assistant to Chief of Air Service on April 27, 1921, and served in that capacity until April 26, 1925; and was air officer, Headquarters Eighth Corps Area, Fort Sam Houston, San Antonio, Texas, to September 22, 1925. He was stationed at Washington, D.C. until February 1, 1926, on which date he resigned from the United States Army.

Brig. Gen. Mitchell was on the Initial General Staff Corps Eligible List.

After his resignation, the general resided at Middleburg, Virginia. He died on February 19, 1936.

Brig. Gen. Mitchell was promoted to captain on March 2, 1903; to major on July 1, 1916; to lieutenant colonel on May 15, 1917; to colonel (temporary) on August 5, 1917; and to brigadier general (temporary) on October 1, 1918. He reverted to his permanent rank of lieutenant colonel on June 30, 1920; and was promoted to colonel, Regular Army, on July 1, 1920, and brigadier general, Assistant to the Chief of Air Corps, on April 27, 1921. Upon the expiration of his appointment as brigadier general, Assistant to the Chief of Air Corps, on April 26, 1925, he reverted to his permanent rank of colonel. The general resigned from the Army on February 1, 1926.

Brig. Gen. Mitchell was awarded the Distinguished Service Cross in 1918, with the following citation:

“For displaying bravery far beyond that required by his position as Chief of Air Service, 1st Army, American Expeditionary Forces, setting a personal example to the United States aviation by piloting his airplane over the battle lines since the entry of the United States into the war, some instances being a flight in a monoplane over the battle of Noyon of March 26, 1918, and the back areas, seeing and reporting upon the action of both air and ground troops, which led to a change in our aviation’s tactical methods; a flight in a monoplane over the bridges which the Germans had laid across the Marne during July, 1918, which led to the first definite reports of the location of these bridges and the subsequent attack upon the German troops by our air forces; daily reconnaissances over the lines during the battle of St. Mihiel salient, September 12 to 16, securing valuable information of the enemy troops in the air and on the ground, which led to the excellent combined action by the allied air services and ground troops particularly in this battle.”

Brig. Gen. Mitchell was awarded the Distinguished Service Medal in 1919, with the following citation:

“As Air Service commander, first of the zone of advance and later of the 1st Army Corps, by his tireless energy and keen perception he performed duties of great importance with marked ability. Subsequently as commander, Air Service, of the 1st Army, and in addition, after formation of the 2nd Army as commander of Air Service of both armies, by his able direction of those vitally important services he proved to be a potent factor in the successes achieved during the operations of the American armies.”

Brig. Gen. Mitchell was also awarded the Spanish War Service Medal, Army of Cuban Occupation Medal, Philippine Campaign Medal, Army of Cuban Pacification Medal, World War I Victory Medal with eight Battle Clasps (Cambrai, Somme Defensive, Meuse-Argonne, Champagne-Marne, Aisne-Marne, Oise-Marne, St. Mihiel, Defensive Sector), Companion of the British Order of St. Michael and St. George, Commander of the French Legion of Honor, French Croix de Guerre with one Silver Star, one Silver Palm and three Bronze Palms, French Pilot Badge, Grand Officer of the Order of the Crown of Italy, Commander of the Italian Order of Saints Maurice and Lazarus, and the Italian War Merit Cross.