The 1912 Olympics was a testing time for many horses and Lt. Jack Montgomery rode the same horse, Deceive, in the Three Day Event, the show jumping and the dressage competitions. He fared best in the Three Day Event, finishing eighth in the individual competition, and winning a bronze medal in the team event. Montgomery also won a bronze medal as a member of the polo team in 1920.
Montgomery graduated from West Point in November 1903 and served the pre-war years with the with the 7th Cavalry and during World War I was accorded the only battlefield promotion made by General Pershing during the entire war. He was also awarded the Distinguished Service Medal. After the war he remained in Germany as Chief of Staff of American Forces. He continued to serve in various posts until gaining command of 1st Squadron 10th Cavalry. He eventually retired as a Colonel on 21 June 1930. After the army he joined the First Boston Corporation and later became a director of the firm which grew to be the largest investment bank in America.