Desnoyers was born at Nogent-le-Rotrou, in the department of Eure-et-Loir. Becoming interested in geology at an early age, he was one of the founders of the Geological Society of France in 1830. In 1834 he was appointed librarian of the Muséum National d'Histoire Naturelle in Paris. His contributions to geological science comprise memoirs on the Jurassic, Cretaceous and Tertiary Strata of the Paris Basin and of Northern France, and other papers relating to the antiquity of man, and to the question of his co-existence with extinct mammalia. His separate books were Sur la Craie et sur les terrains tertiaires du Cotentin (1825) and Recherches geologiques et historiques sur les cavernes (1845).