After being drafted into the Army, serving as a conscientious objector, Tuttle continued to run. It was at this time he attempted his first marathon, finishing second in the first and winning the second. In 1975 he was the fourth ranked marathoner in the United States and was considering himself a marathoner. He won the National Championships in the Marathon in both 1975 and 1976 Only one person since Tuttle has successfully repeated as National Champion He also was the first National Champion at 15 kilometers and also won the National Championship at 25 kilometers. He placed seventh overall at the 1976 IAAF World Cross Country Championships.