- First World War (1914-1918)
- Lieutenant Colonel
- Assistant Chief of Staff, G-3, American Expeditionary Forces (AEF), U.S. Army
- Awarded on:
"For exceptionally meritorious and distinguished services to the Government of the United States, in a duty of great responsibility during World War I. As Assistant Chief of Staff, 82d Division, First Assistant to the Assistant Chief of Staff, G-3, 3d Army, and later as Assistant Chief of Staff, G-3, American Expeditionary Forces in Germany, by his untiring energy, devotion to duty, and exercise of initiative Lieutenant Colonel Wainwright contributed in a large measure to the success attained by the commands with which he served."
War Department, General Orders No. 19