Leary arrived at Fordham in 1939 and proceeded to win the Metropolitan IC4A three-mile race as well as take 3rd in the Freshman IC4A three-mile race. As a sophomore in 1940, he took second place in the Metropolitan IC4A cross country race and was a member of the two-mile indoor relay team which won six of their eight races. He also ran the 1000 yard run, winning the Metropolitan IC4A championship and placing third in the National Track & Field Meet. The following year, his two-mile relay team won seven indoor races, setting two meet records in the process and successful defended his Metropolitan IC4A 1000 yard title in record time.
 
After serving in the U.S. Navy from 1942-45, Leary returned to Fordham for the 1946 outdoor season and was named team captain. He won first place at the Metropolitan IC4A 880-yard run and in the 1947 indoor season, he was a member of the winning two-mile relay team at the Penn Relays.