René Deynis made his debut as an illustrator for the magazines Fillette and Vaillant. For Vaillant, Deynis took on drawing comics in 1959 by succeeding Jacques Souriau on 'Jean et Jeanette'. Three years later he did the artwork for the 'Jacques Flash' series after Pierre Leguen and Gerald Forton. After doing some illustration work for a few magazines (Radar, Amis-Coop, Pilote), Deynis turned to writing scenarios due to an injury on his hand.
For six years, he wrote the series 'Les Espadons' for Gaty and Dominique Sérafini in Le Journal de Mickey. In 1975 however, René Deynis took on drawing again, taking on 'Oscar Mittoman' in Tintin and two educational comic books at Chancerel/Fleurus. In the 1980s he joined the Five Stars Studios, where he worked on series such as 'Albator' for the periodical Captain Fulgur, together with Pierre Leguen, Christian Gaty, Max Lenvers and Philippe Luguy.