Boulnois attended the Conservatoire de Paris, where he studied counterpoint with Georges Caussade and organ with Louis Vierne.
In 1906, he married the pianist Jane Chevalier, and they had a son the following year, Michel Boulnois, who also became a composer and organist.
He stayed there a short time and was appointed to the organ of the Église Saint-Louis-d'Antin [fr] in the 9th arrondissement.
He also played in the Opéra-Comique and performed in the Église Saint-Dominique de Paris [fr] church in the 14th arrondissement.
After the beginning of the First World War, Boulnois was mobilised at the Février Hospital of Châlons-sur-Marne, where he was a nurse[1] from 1 January 1915.