[3][4] After graduating from the Military Academy, Gillespie served in the United States Army until December 1946, attaining the rank of brigadier general.

[5] He was stationed in the Philippines at the outbreak of World War I and returned to the United States for wartime service at Camp Grant before being sent to France.

After the war, he served as a military attache in Tokyo and then spent four years as an ordnance and gunnery instructor at West Point.

[1] Gillespie graduated from the Command and General Staff School in 1924 and the United States Army War College in 1929.

[2] He died in January 1956 at the Walter Reed Army Medical Center in Washington, D.C.[2] Gillespie was buried at Arlington National Cemetery.