Served in WWI in the 6th Infantry Regiment and was promoted to the rank of lieutenant colonel. In WWII, he was put in command of the 9th Armored Division as Major General. Retired from the army in 1952.
John William Leonard was born on January 25, 1890 in Toledo, Ohio as a son of Dennis and Anastasia Leonard. He graduated from the United States Military Academy in 1915, as part of "the class the stars fell on", a famous class of West Point, from which Dwight D. Eisenhower or Omar N. Bradley graduated. Many years later Dwight D. Eisenhower would introduce to John to wife. His first war service was at Mexico – United States border. Then, in May 1918, he was sent as a member of the 6th Infantry Regiment of the 5th Infantry Division within American Expeditionary Forces to the France. Reaching the rank of Major, Leonard commanded a Battalion of the 6th Infantry Regiment during Battle of Saint-Mihiel and Meuse-Argonne Offensive. For his bravery on the battlefield near the village of Romagne-sous-Montfaucon, Major Leonard was promoted to the rank of Lieutenant Colonel and decorated with the Distinguished Service Cross, Purple Heart French Legion of Honor, Croix de Guerre with Palm and French Fourragère. After the war, Leonard stayed in Europe for occupation duties until October, 1921. Then he served on various posts including a posting to Tientsin China 1933-1936. In 1936, Leonard was appointed an Instructor for Maryland National Guard and stayed in this capacity until 1940. Then he spent some time on the staff of the 2nd Infantry Division under command of Major general James Lawton Collins. During the year 1941, Leonard was promoted to the capacity of the commanding officer of the 6th Armored Infantry Regiment, which was now a part of the 1st Armored Division under the command of Major general Bruce Magruder. During this time, 6th Armored Infantry Regiment was stationed with whole 1st Armored Division at Fort Knox in Kentucky. Leonard was promoted to the rank of Brigadier general on June 20, 1942. During the summer of 1942 Brigadier general Leonard was put in command of the newly activated 9th Armored Division at Fort Riley, Kansas. In this capacity, Leonard replaced Major general Geoffrey Keyes at the end of September, 1942.[5] On October 27, 1942, Leonard got his second star, when he was promoted to the rank of Major general. Two years later, in September 1944, 9th Armored Division was transferred to the United Kingdom, from where it was immediately ordered to Normandy. Leonard continued as its commander until the end of the war, when he became commander of the 20th Armored Division. During the period between the wars, he served as commandant of the Armor School from 1946, and as military attaché in the United Kingdom from 1948. In 1950 he was promoted to Lieutenant General and commanded both the V Corps and XVIII Airborne Corps. He retired from the army in 1952.