After playing top-flight amateur hockey while still in high school, Tony Conroy joined the St. Paul Athletic Club and helped them win the McNaughton Trophy in 1916-17. St. Paul then took on Lachine, Quebec, for the Ross International Cup and won, despite being forced to play six-man hockey for the first time (hockey started as a seven-man sport). Conroy served in the Army Aviator Corps during World War I.
Conroy played for the 1920 Olympic team and still holds the U.S. Olympic record for most goals scored in one game – 10 against Switzerland in a 29-0 rout. In 1925 the St. Paul Club turned professional and became the St. Paul Saints. Conroy stayed with them until 1929, despite offers to join the NHL.