At the age of 19, Ben Lear joined the Colorado National Guard and soon saw service in the Spanish-American War and in the Philippines. He rose through the ranks to become a lieutenant general and earned the reputation of being a reserved officer and a harsh disciplinarian. Questions were asked in Congress about his ordering a regiment of citizen-soldiers on a 15-mile disciplinary march but the controversy was forgotten when the Japanese attacked Pearl Harbor five months later. Lear was the leading U.S. rider in the 1912 Olympic Three Day Event, finishing in seventh place. He was also a member of the team which placed fourth in the Show Jumping and Lear himself finished 12th in the field of 21 riders.