De Beck's career coincided with a strong period of men's long-distance running in Belgium in the 1970s, with Roelants, Willy Polleunis, Emiel Puttemans, Karel Lismont and Ivo Van Damme being the other protagonists. The 1973 IAAF World Cross Country Championships marked the inauguration of the modern world championship event and, held on home turf in Waregem, the Belgian trio of Polleunis, Roelants and De Beck won the first team title (De Beck placed 18th individually). De Beck won his first national title in cross country a year later. He produced an upset at the 1974 IAAF World Cross Country Championships by winning the title just ahead of Mariano Haro (the 1973 runner-up) and leading the Belgian men to the team gold medal.