Born in Rouen, Stéphane Gess eventually settled in Nantes. After some artistic jobs, Gess began his comics career in the Rouen fanzine Café Noir. He made his true debut with 'Teddy Bear', that appeared at the publishing house Zenda between 1992 and 1995. Olivier Vatine suggested that Gess started a new series in the Série B collection of Delcourt, and this resulted in the science-fiction detective series 'Carmen Mc Callum', that he drew from 1997 to 2007.
In addition to this series, Gess does covers and illustrations for the publishing house L'Atalante, and he cooperates on the comic series 'Ultima Parano' with fellow artist Steph and writer JB. He is also the scenarist of the series 'Kazandou', that is drawn by Humbert Chabuel. In 2009 and 2010 he drew 'La Brigade Chimèrique' from scripts by Serge Lehman and Fabrice Colin for the publisher L'Atalante. He drew an installment in the collective series 'Jour J' by Jean-Pierre Pécau, Fred Duval and Fred Blanchard for Delcourt in 2011.