Agricola served mostly at the Western front, and although he never received a troop command throughout the war (only staff assignments), this indicated that he was destined for a more ambitious career than most of his fellow troop officers; he became Adjutant of a battalion in his regiment on 2 August 1914, participated in the battle of the Marne in September and was promoted to "Oberleutnant" (First Lieutenant) in December. In early January 1915 he served as the regimental Adjutant of his pre–war regiment until August 1916, when he was temporarily elevated to Brigade Adjutant. In that capacity, he saw action at the Battle of the Somme, where he distinguished himself numerous times. On 9 January 1917 he was transferred to the staff of the 219th (10th Royal Saxon) Infantry Division, occupying a relatively quiet sector of the front line in Lorraine. A few weeks later, on 27 January, he was promoted to "Hauptmann" (Captain) and four days later, the last King of Saxony, Frederick Augustus III, bestowed him with one of Saxony's highest decorations, the Military Order of St. Henry, in recognition of his conduct during the battle of Somme the previous year. He received his last wartime assignment on 25 May 1917, when he was transferred to the staff of the XII (1st Royal Saxon) Army Corps. Becoming a staff officer — a group considered the "élite" of the German Army — required a three–year course at the War Academy in Berlin after some years of active service. Agricola's ambition to become a staff officer, however, was thwarted by the war, as the War Academy closed upon its outbreak. Apart from his relevant staff appointments, he had the chance to participate in a special staff officers course from January to February 1918. During the course of war, he was decorated with numerous awards, including both classes of the Iron Cross and other awards from his native Saxony. Following the end of World War I in November 1918, Agricola was retained in the Reichswehr holding a variety of staff roles. He was promoted to Major in 1928. From 1927 to 1930, he commanded a company of the 10th Infantry Regiment. In February 1930 he returned to the staff of "Gruppenkommando 1" and in 1931 to that of the 4th Division, where, as an "Oberstleutnant" (Lieutenant Colonel) from 1932, he saw the rise of the Nazi regime in 1933.