Henri Desclez created his first comics in cooperation with scenarist Michel Noirret, which were published in Pilote in 1967 and 1968. A year later, he joined Le Soir-Jeunesse, where he took on the 'Mircroft et Klaxon' series with André-Paul Duchâteau. Also for this magazine, he drew 'Le Tailleur de Londres' and 'Les Mystères de Bruges' under the pseudonym Hapic. Again with Duchâteau, Desclez illustrated 'Saint Fauston' in Tintin in 1969, and 'Richard Bantam' for Spirou in 1970. The latter series was later drawn by Henri Decoster.

In 1972 he founded Studios Desclez, through which he produced comic adaptations of the 'San-Antonio' series, co-drawn by Franz and published by Fleuve Noir. That same year, Desclez became editor-in-chief of the Belgian edition of Pilote, where he opened the doors for many national artists. In 1975, he succeeded Michel Greg as editor-in-chief of the Belgian version of Tintin. In Tintin, he also illustrated 'Les Chroniques du Griffon Noir' and 'Gaspard le Bâlois'.
Desclez then moved to Canada, where he founded his own publishing house, which published comics by Canadian artists as well as detective novels by André-Paul Duchâteau. In addition, Desclez produced new comics himself, such as 'Brisebois', 'Pic et Nic' (both co-written by Andrée Brault), 'Diogène' and 'Monsieur Tranquille'. In 1980, he edited the SF magazine L'An 2000 and the fantasy review Misty. He founded a new studios, which produced the educational series 'Les Mics et les Miquettes'. Desclez eventually turned to painting.