Contemporaries, such as Adrian Willaert (as quoted by the renowned Venetian theorist Zarlino) grouped him with Josquin, Ockeghem, and Jean Mouton as among the finest composers of the time.
The first is that he was associated with the French royal court, for he wrote several motets for official occasions (such as the coronation of King Francis I in 1515); this would have put him there at the same time as Jean Mouton and just after Antoine de Févin.
In addition, one document describes him as a priest of the Meaux diocese, and also associates him with the cathedral in Tours; it also names him as a singer in the royal chapel in 1517–1518.
Adrian Willaert, the founder of the Venetian school, also held Gascongne in high regard, stating that he was on the level of Josquin, Ockeghem, and his own teacher Jean Mouton.
Most of his sacred music is for four a cappella voices; he uses as source material chansons by Pierre de la Rue, Jean Mouton and Josquin des Prez.