Two-time Olympian John Andru made his Olympic debut in fencing at Tokyo 1964 where he competed in the individual foil, epée and sabre events. At Mexico City 1968, he competed in the individual sabre, and foil and epée team events. At both Olympics, he did not advance out of the first round of any of his competitions.

A six-time British Empire and Commonwealth Games medalist, Andru competed at three consecutive Games capturing three silver (1958 and 1966 team epée, 1962 team sabre) and three bronze (1962 sabre and team foil, 1966, team sabre) medals. Andru competed at two Pan American Games winning three bronze medals in 1959 (foil team, sabre team) and 1967 (sabre team).

Andru fenced at the University of Toronto where he was awarded the 1956 George Tully Trophy (the fencer most proficient in skill, style and sportsmanship). He was inducted into the Canadian Olympic Hall of Fame in 1976.