Little is known of his life, but internal evidence in his compositions indicates he was probably at the French royal chapel during the first two decades of the 16th century, at least, and was also associated with the cathedral in Meaux, on the Marne east of Paris.
Documents from the Vatican (1505–1513) help establish his identity, as they indicate that a "Petrus Moulu" held various clerical positions at Meaux Cathedral.
He may have written his mass Stephane gloriose, for the cathedral of St Etienne (Saint Stephen) in this town.
In addition to the masses, Moulu wrote motets and chansons, some of which are of doubtful authorship (Mouton and Josquin are also suggested as the composer for several of these pieces).
For example, as late as 1592, an untexted 3-voice canon appears in Lodovico Zacconi's Prattica de musica under the name 'Pietro Molu'.