 Between the wars, Krueger served in a number of command and staff positions, and attended the Naval War College at his own request. In 1941, he assumed command of the Third Army, which he led in the Louisiana Maneuvers. He expected, in view of his age, to spend the war at home training troops, but in 1943 he was sent to General Douglas MacArthur's Southwest Pacific Area as commander of the Sixth Army and Alamo Force, which he led in a series of victorious campaigns against the Japanese. As an army commander, Krueger had to grapple with the problems imposed by vast distances, inhospitable terrain, unfavorable climate, and an indefatigable and dangerous enemy. He had to balance MacArthur's need to speed up the tempo of operations in order to win campaigns with the more cautious approach of subordinates who often found themselves confronted by unexpectedly large numbers of Japanese troops. In the Battle of Luzon in 1945, his largest, longest and last battle, he was finally able to maneuver his army as he had in 1941 against a Japanese army under Tomoyuki Yamashita.
