After following artistic studies, he worked as an advertising illustrator for ten years. Drawn to storytelling, he started making comics in the late 1970s. His first album, 'Trucker', was published by Becker und Knigge in 1978. In 1981, he started a series of comic adaptations of short stories by the American writer Charles Bukowski, collected in an album by Heyne. In addition, Schultheiss did artwork for several communication and press assignments, and he illustrated the section 'Die Grüne Hölle' in Stern magazine.
Since 1982, he was present on the French market with contributions to magazines like L'Écho des Savanes and USA Magazine. In 1985, he made 'Guerres Froides' ('Kalter Krieg') with the publihsing house Albin Michel. For this same publisher, he began the series 'Le Théorème de Bell' ('Die Wahrheit über Shelby'), prepublished in L'Écho des Savanes. For the magazine Circus of the publishing house Glénat, he made 'Le Rêve du Requin'. He made his first cinematographic storyboard, 'Le Chant des Baleines', in 1986. A year later, he produced 'Stromer' for the German publisher Hummel.
In 1990, Schultheiss made the independant comic book 'Night Taxi', which was published by Carlsen in Germany and by Delcourt in France. He then took on the erotic story 'Sois Vicieux' ('Talk Dirty'), which was published by Glénat and Hummel.