He was expected to succeed Théodore Dubois as director of the Conservatoire in 1905, but his chances evaporated when he was implicated in an attempt to rig the results of that year's Prix de Rome in favour of his own pupils.
The young Lenepveu received a traditional education in his home town, while at the same time teaching himself musical theory and learning to play the violin.
[2] The following year he won France's most prestigious musical award, the Grand Prix de Rome, with his cantata Renaud in the Gardens of Armida to words by Camille du Locle.
While there he successfully took part in a competition for dramatic composition; his three-act comic opera Le florentin, to a libretto by Henri de Saint-Georges.
[2] Before the delayed presentation of Le florentin Lenepveu's Requiem Mass was performed at Notre-Dame de Bordeaux in 1871, won critical approval, and was given in Paris the following year.
When Ambroise Thomas died in 1896, Lenepveu was elected to succeed him as a member of the Académie des Beaux-Arts, beating his rival candidate, Gabriel Fauré, by nineteen votes to four.
He was denounced by the leading critic Pierre Lalo as "a poor musician, author of a few worthless compositions; without ideas or art; but he is a member of the Institut".