A contemporary of the Impressionists, Delpy blended the subject matter that he adopted from Daubigny with the brighter colors and looser paint handling that were trademarks of his own generation to create distinctive new visions of many of the landscapes first explored by the Barbizon artists.
In the early 1870s, Delpy worked often in Ville-d'Avray, Corot's favored country site, and in Auvers-sur-Oise where Daubigny lived.
In 1875, exhibited a snow scene at the Salon for the first time and was complemented by the critic Jules-Antoine Castagnary for his originality.
In 1876 Delpy organized a sale of his own paintings at the auction house Hôtel Drouot, an unusual undertaking.
In 1886, Delpy traveled to the United States as part of a team that painted a panorama of the battle of Manassas (American Civil War) in Washington DC.