Appleby's greatest period of success in football was during the 1960s when the first team achieved a string of almost unbroken winning seasons. The best seasons were 1966 and 1967 when the team went undefeated in inter-scholastic play. The success of the 1967 team, in particular, who defeated not only Appleby's Old Boys in an exhibition game, but each of the first teams of the "Little Big Four" schools, Upper Canada College, St. Andrew's College, Ridley College and Trinity College School, led to Appleby joining the CISAA, where all of Appleby's different sports teams have competed since.