 Wagner was born in Le Pré-Saint-Gervais, Seine-Saint-Denis.He began racing cars while in his teens and claimed victory in 1903 driving a Darracq in a "voiturette" class race at the Circuit des Ardennes at Bastogne, Belgium.Wagner was one of the drivers for the Darracq team in the 1904 Gordon Bennett Cup in Germany that finished 8th and in 1905 at the Circuit d'Auvergne in Clermont-Ferrand, he was eliminated in the first round.