Born in 1946, Gilbert Declercq did his art-studies at The Royal Academy in Gent (Belgium). Since then he is working as a freelance painter, illustrator and comic-artist.

He began his career in Ons Volkske at the age of 16, with the realistic short story 'De D-558-2 Skyrocket'. He made illustrations in female magazines, like Mimosa, Rosita, Libelle and Het Rijk der Vrouw.

Commics and illustrations were published in many magazines and books in different countries. Clients for example: Readers' Digest, Daimler Chrysler, Greepeace, Märklin, Dai Nippon, etc...

From 1971, he did illustrations and covers for Ohee. In Le Soir, he created 'Hugo des Ombres' with text by André-Paul Duchâteau in 1974. A year later, he illustrated the John Flanders adaptation 'De Witte Tijger' with text by Serge Bertrain (Danny de Laet) in Het Gazet Van Antwerpen. From 1974, he assisted Eddy Ryssack on his comics. In the late 1970s, he did comics for Top ('Devoon en Carboon') and Het Gazet van Antwerpen ('De Lotgevallen van Terry Trom'). He had his breakthrough with the aviation series 'Rud Hart', that appeared in the Dutch Eppo from 1977. For the publisher Lombard, he created 'Jody Barton' in 1991. He dropped most of his comics activities to devote himself to illustrating and painting. He is a regular contributor to the Dutch girls magazine Tina.

Gilbert 's work has been exhibited in for example The Mall-Galleries (London), National Maritime Museum (Antwerp, Belgium), European institute (Wien), Museum of American Illustration, Mystic Maritime Gallery and many galleries in Belgium, Austria, Italy, etc... and his watercolors won several national and international prizes (one juried bij The Royal Watercolor Society, England). Work is in State collection: National maritime Museum (Antwerp, Belgium), National Institute for Fishery (Ostend, Belgium), City of Innsbruck (Austria), Potterie Museum (Brugge, Belgium).

Gilbert Declercq became an artist-member of the society of Illustrators (New York) in 1984.