Born to a noble family du Passage began his career as a second lieutenant in the 9e Carabiniers at Maubeuge. He first exhibited at the Salon in 1865 and following his success there, decided to give up his military career and concentrate solely on his art. He was fortunate enough to study under two of the most important sculptors of animals of the day, Pierre-Jules Mêne (1810–1879) and Antoine-Louis Barye (1795–1875), and like Mêne specialised in equestrian models, hunting scenes and lifelike depictions of dogs.