He was named ordinaire de la musique (Director of Music of the Chapel and the Apartments) by Louis XV in 1733, Leclair dedicated his third book of violin sonatas to the king.

[2] Leclair was then engaged by the Princess of Orange – a fine harpsichordist and former student of Handel – and from 1738 until 1743, served three months annually at her court in Leeuwarden, working in The Hague as a private maestro di cappella for the remainder of the year.

From 1740 until his death in Paris, he served the Duke of Gramont, in whose private theatre at Puteaux were staged works to which Leclair is known to have contributed.

In 1758, after the break-up of his second marriage, Leclair purchased a small house in a dangerous Parisian neighbourhood in the northern part of Le Marais near the old Temple, where he was found stabbed to death on 23 October 1764.

[4] Although the murder remains a mystery, there is a possibility that his ex-wife may have been behind it—her motive being financial gain—although suspicion also rests strongly on his nephew, Guillaume-François Vial, an embittered violinist who desperately wanted employment.