He was a passionate right back at Anderlecht who had to fight and defend himself. He was not the most talented of the greats around him, but built an excellent career based on determination and perseverance. Heylens never tired, he helped in attack and had a good header despite his smaller size. He was a national team player for 12 years before a broken leg ended his career in 1973. He played at the 1970 World Cup and the European Championship in 1972.