Kilpatrick ran Madison Square Garden for more than twenty-five years, personally overseeing the operations of the New York RangersNHL club from 1934 to 1960. The Rangers won the Stanley Cup in 1940 while he was in charge. Kilpatrick introduced a number of other professional events at Madison Square Garden, such as ice shows and, with the assistance of Ned Irish, college and professional basketball player. In 1936, he was elected an NHL Governor.
In June 1942, Kilpatrick was recalled to active military duty to serve in World War II and was promoted to brigadier general. He retired from the army in 1949 and resumed his career at Madison Square Garden.