Throughout the 1930s, he was a shortstop and second baseman for various minor league baseball teams, including the Newark Bears and the Binghamton Triplets.
The same year, Leishman was named director of multiple Yankees affiliated teams including the Victoria Athletics and the Bisbee-Douglas Copper Kings.
[6] Leishman stayed in the PCL as front-office boss of the San Diego Padres from 1960 to 1968, under owner C. Arnholdt Smith.
Although Bavasi was integrally involved in the team's baseball operations, Leishman was retained as general manager of the MLB Padres until his death in 1972.
[7] During his career, Leishman was twice honored as Minor League Executive of the Year by The Sporting News, in 1959 with Salt Lake City and 1964 with San Diego.