Starting in 1749, he was the pupil of Jacques-François Blondel at l'École des Arts, where he met William Chambers and had as a schoolmate Marie-Joseph Peyre; later he studied with Giovanni Niccolò Servandoni and with Jean-Laurent Le Geay.
In Rome, de Wailly founded a friendship with the sculptor Augustin Pajou, who was to carve his bust and that of his wife and for whom, in 1776, he would build a house adjoining his own, in Paris.
His reputation abroad grew through engravings of his works; he became particularly popular in Russia, where his disciples, some of whom went to Paris to study with him directly, included Vasily Bazhenov, Ivan Starov, and Andrey Voronikhin.
The following year, he was authorized to leave for a long stay in Genoa, to redecorate the seventeenth-century palace of Cristoforo Spinola in the Strada Nuova,[5] working in tandem with Andrea Tagliafichi: the building was badly damaged in 1942.
He married Adélaïde Flore Belleville who, after his death, remarried in 1800 to the chemist Antoine François, comte de Fourcroy.