After the end of World War II Enrique Demarco had a brief career as a road cyclist, mainly competing in races in his native Uruguay. In 1946 Demarco finished third on the opening stage of the Tour of Uruguay, before finishing fourth overall in the general classification. Two years later he won the fifth stage of the race and finished seventh overall, earning himself a place on the Olympic team. At the 1948 London Games he competed in the road race but did not finish the course. One year later Demarco had another podium finish at his home race when he came third on the fourth stage.