Michel Constant took courses in comics at the École Supérieure des Arts Saint-Luc in Liège. He then teamed up with scenarist Denis Lapière with whom he created the series about car mechanic 'Mauro Caldi' for Éditions du Miroir. The series was later continued at Alpen publishers, and eventually revived after twenty years at Paquet in 2014. In addition, Constant and Lapière created two short stories for Tintin Reporter. From 1995, Constant drew 'Bitume', a collection of independent stories written by Michel Vandam.
Early in his career, Michel Constant was inspired by the "School of Marcinelle" (Jijé, Tillieux), but along the way, he took on a caricatural realism, which reminds of the work of Charles Burns. Since 2002, Constant has worked on a regular base with writer Jean-Luc Cornette, resulting in the detective comic 'Red River Hôtel' (Glénat, 2002-2005), the humor series 'Au Centre du Nowhere' (Le Lombard, 2005-2008), the historical comedy 'Le Pygargue' (Quadrants, 2011) and the social science fiction book 'Le Sourire de Mao' (Futuropolis, 2013). He did both script and art on his 2010 one-shot 'Rue des Chiens Marins' in the collection Signé of Le Lombard.