[1] Fleming joined the Louisiana National Guard in 1916 and served on the Mexican border during the Pancho Villa Expedition, attaining the rank of Sergeant.

Assigned to the 141st Field Artillery Regiment, he served in France throughout World War I, advancing to captain as commander of Battery D. His unit was mustered out in 1919, and he returned to Louisiana.

[6] Fleming also continued his academic studies by undertaking post-graduate work in economics and labor relations at Tulane University.

Allen, in 1934 Fleming deployed National Guardsmen to the offices of election officials in New Orleans when Allen declared martial law during a disputed election between the Long-Allen group and a group headed by Mayor T. Semmes Walmsley.

[14] From 1940 to 1947 Fleming also concurrently served during World War II as the federal Director of Selective Service for Louisiana.

[15] In 1946 Fleming was named commander of the 39th Infantry Division, an assignment he carried out while still serving as Adjutant General.

[19] In 1950 Fleming was named acting Chief of the National Guard Bureau, succeeding Kenneth F.

[20] In 1951 Fleming's nomination was confirmed, and he served as NGB Chief until reaching the federal military's mandatory retirement age in 1953.