[1] 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.
[6] 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.
[6] He failed to repeat his previous success at the 1976 IAAF World Cross Country Championships, coming 49th, although Belgium took the team silver medals.
[8] His teammate Léon Schots won the gold at the 1977 IAAF World Cross Country Championships and De Beck's 18th-place finish saw him share in the team title for a third time in his career.
[6] His last year of major competition came in 1987: he finished 73rd at the 1987 IAAF World Cross Country Championships and won the Zwijndrecht Marathon in a time of 2:21:50 hours.