Major Edmund Maginnis Barnum graduated from the Command and General Staff School on 19 June 1931. During World War II, in 1942 Colonel Barnum served as Chief of Army Exchange Service in the Headquarters, Services of Supply, in the European Theater of Operations.

He was awarded the Legion of Merit.

Death and Burial

Colonel Edmund Maginnis Barnum died on 27 October 1943 and is buried at the Cambridge American Cemetery and Memorial in Coton, Cambridgeshire, England, in Plot F, Row 4, Grave 35.