Keyser remained on the staff of 2nd Army Division during the Meuse-Argonne Offensive and following the Armistice in November 1918, took part in the Occupation of the Rhineland in Coblenz. He was decorated with the Army Distinguished Service Medal for his service as Divisional Intelligence officer and also received Légion d'honneur, rank of Knight, French Croix de guerre 1914–1918 with Palm and Gilt Star and Belgian Order of the Crown, rank Officer.