Prior to the United States entry into the First World War, David H. Backus volunteered as an ambulance driver for the Red Cross, where he spent three months in the Chemin des Dames evacuating the dead and wounded. He was awarded the Fourragère of the Médalle Militaire from the French Government for his work.

Backus received his flying rating at Tours, France in November of 1917. During his air service he was credited with the destruction of four enemy aircraft and was eventually awarded the Distinguished Service Cross with Oak Leaf Cluster, the French Croix de Guerre with Palm, and the Fourragère of the Médaille Iliatrie.

Backus volunteered for active duty at the start of the Second World War and was appointed major in the Army Air Force in February of 1942. He served several roles in World War II. Initially, he was an Intelligence Officer with the 305th Flying Fortress Bombing Group in France and Germany but he was also an air intelligence and public relations officer in Lt. General Jimmy Doolittle's 12th Air Force Service Command in the North African, Sicilian, and Italian Campaigns. It was during his time in North Africa that Backus took many of the photographs used as official publicity for the Air Force at the time. Many of the photographs from that period are included in the collection with annotations.

Backus was also an assistant chief of staff for intelligence and public relations with the 15th Air Force Service Command. He was on detached service with the War Department for six weeks in 1944 as a speaker at aircraft manufacturing plants and led a special tour of midwestern states to promote the use of corn for essential war production.

David Backus' parents, Clinton J. and Carrie Haskins Backus, were both employed at Baldwin Seminary from 1884, which eventually became Oak Hall/Mrs. Backus' School for Girls. Mrs Backus was principal of the St. Paul-based preparatory school from the early twentieth century until she sold it in 1918.