Born in Elby, Michel Pierret studied at the École Supérieure des Arts Saint-Luc in Liège. He published his first comics in the "Cartes Blanches" section of Spirou magazine from 1974. He also made the series 'Terran Stone' for this magazine before joining the publishing house Lombard. He drew 'Les Aventures de Papilio' in Tintin from 1979 to 1987. In 1986, he also made on 'De l'Autre Coté de l'Écran' and the humorous series 'Max et Cati' for this magazine.
In 1990 and at the publishing house Glénat, he took over the artwork of 'Les Aigles Décapités' from Jean-Charles Kraehn, who continued to do the scriptwriting. As a scriptwriter, Pierret has written 'Les Diables Bleus' for Francis Carin in Spirou (1980), 'Hidalgos' for Marco Venanzi (Glénat, 2003, 2007), 'Les Déesses' for Jacques Denoël (Glénat, 2005-07).
Together with Venanzi, he has also done the artwork for 'Opération Dragon Rouge' from a script by Thierry Robberecht and for 'Le Protocole Aïda' from a script by Yannick Laude, published by Casterman in 2006 and 2008. Michel Pierret has also made comic adaptations for Je Bouquine.