Claude Lacroix began his career as a comic artist and illustrator at age twenty. He published his first humorous drawings in L'Os à Moelle in 1964, and he later worked for such magazines as Candide, Arts et Loisirs, Elle, Plexus, Hara-kiri, La Vie française, and 60 Millions de Consommateurs.
As a comic artist and writer, he started out contributing to Les Pieds Nickelés and Lisette, for which he created the series 'Farfelune'. He subsequently published in Métal Hurlant, Pilote, Formule 1, Gomme!, Okapi and Je Bouquine. He made six books of the series 'Yann le Migrateur' with Robert Génin for Glénat between 1978 and 1984, and wrote and drew 'L'homme au chapeau mou' under the pseudonym Tartempion from 1979 to 1982. Under the pseudonym Alias, he made the science-fiction comic 'Fariboles sidérales' for Les Humanoïdes Associés in 1979. In 2006, he made a comic about the Notre Dame de Paris with Serge Saint-Michel for the series 'Des Monuments et des Hommes' of Éditions du Signe.
Lacroix also writes the scenarios for François Bourgeon's science-fiction series 'Cyann' since 1993. He has worked as a journalist and illustrator for magazines like Jeux et Stratégie, Le Journal de Mickey, Le Point, Science et Vie. He founded the Atelier Bergame in 1988 with artists Régis Loisel and Pierre-Yves Gabrion.