At Boys' Latin School, Don earned eleven varsity letters as a starting player, and was an All-Maryland selection at attack in 1945 and 1947. He was captain of the 1947 team. He continued his career at Princeton University playing on the freshman team in 1948. As an upperclassman Don made honorable mention All-American in 1949 and first team All-American in 1950 and 1951. He received Princeton's biggest lacrosse honor, the Higgenbottom Trophy, in 1950 and 1951. As captain of the national co-champions he established a three-year scoring record of 52 goals and 107 assists and was awarded the Turnbull award in 1951.
Following graduation from Princeton, Don entered the Johns Hopkins Medical School and received his M.D. in 1955. During medical school, Don coached Boys Latins' seventh, eighth, and ninth grade football and lacrosse teams, and scouted for Princeton. After graduation from medical school, Don served a residency in internal medicine at Belleview Hospital in New York City, and later entered the U.S. Air Force Medical Corps. He served as a captain in Korea and Germany, and finished his residency in internal medicine at Pacific Presbyterian Hospital in San Francisco. In 1965, Don established his medical practice in the historic community of Mendocino in Northern California - a town that had not had a doctor in nearly twenty years.
Don Hahn passed away in February, 2014 at the age of 84.