Leekens made his debut as a footballer in 1967 with after leaving the lower ranks of the club. In 1969, he signed for one year with KFC Dessel Sport. After a brief stint at Crossing Club, he was transferred to Club Brugge. With the team, he reached the final of the UEFA Champions League in 1978 against Liverpool in Wembley Stadium in London where they were defeated with a single goal. He also won five Belgian leagues, a Belgian Cup and a Belgian Super Cup in 1980, one year before joining the Sint-Niklase in which he retired from football in 1984.