Wanting to become a painter, Jean-Paul Dethorey took courses at the School of Fine Arts in Nancy, France, together with Claude Dubois. He made his comics debut in 1964 in Amis-Coop, with 'L'Inspecteur X' (which ran until 1987) and 'Batistin et Big Boogie', a humorous western written by Frank Giroud. In the second half of the 1960s, Dethorey produced comics for Lisette, J2 Magazine, Formule 1 and Fripounet. For this last magazine, he created series like 'Bébé-Chat', 'Inspecteur Tempo' and 'Les Increvables'.
In 1982, while still creating humorous stories, Dethorey also started creating realistic comics for grown-ups. Again with Frank Giroud, he started 'Louis la Guigne', a series that ran in Circus magazine and later Vécu. He continued working for Vécu with 'Le Voyage du Bateleur' (scenario Autheman) and 'Un Crime Ordinaire' (scenario Daniel Bardet). In late 1990, Dethorey started the series 'Coeur Brûlé' with Patrick Cothias, about Germain Granpin, one of the characters from Cothias's series 'Les Sept Vies de l'Épervier'. Dethorey also drew 'L'Oiseau Noir' (text Le Tendre) and 'L'Exécution' (text Dethorey himself) in Dupuis's Aire Libre collection. Dethorey died in 1999, leaving the second part of his final comic, 'La Passage de Venus', unfinished.