Agase entered the U.S. military in 1943 as America's involvement in World War II intensified. He was sent to Purdue University for training in the U.S. Marines and played on the school's football team along with enlistees from other schools. Purdue had won just one Big Ten Conference game the previous year, but the influx of trainees including Agase led to a reversal of fortune in 1943. Coached by Elmer Burnham, the Purdue Boilermakers won all of their games that year and were named Big Ten co-champions. Agase was again named an All-American.