In 1740 he added a second position at the church of Notre Dame de la Ronde, which he maintained with the help of his sister Marie-Anne-Agathe, who substituted for him.
In 1742, after the death of his father, Duphly decided to move to Paris, where he abandoned playing the organ altogether and devoted himself to the harpsichord.
[3] According to Louis-Claude Daquin: For some time he was organist at Rouen, but doubtless finding that he had a greater gift for the harpsichord, he abandoned his first instrument.
In 1788, an advertisement in the Journal Général de la France asked: We want to know what happened to M. du Phly, previously harpsichord master in Paris, where he was in 1767.
His late music contains elements typical of the early classical movement - e.g. the use of Alberti bass, quite dissimilar to Jean-Philippe Rameau or François Couperin.