Mercier was born in Berlin in 1689, the son of Pierre Mercier and of Marie Biendovienne. According to George Vertue, he studied under Antoine Pesne in Berlin, subsequently going on a tour of Italy and France. In 1716 he came to England, recommended by the court at Hanover, and settled on Saint Martin's Street, in the French quarter of London. There, in 1719, he married Margaret Plante, and they had two sons. After Margaret's death he married, in 1735, Dorothy Clapham, with whom he had a daughter. In the mid-1720s he introduced the conversation piece into England; the genre was taken up by Hogarth and rapidly became popular. He was a member of the Saint Luke's Club of Virtuosi, and was steward in 1728; he seems also to have been active as an art dealer.
In 1729 Mercier was appointed Principal Painter to Frederick, Prince of Wales, subsequently being appointed Gentleman Page of the Bedchamber (1729) and Library Keeper (1730). Frederick, a cultivated connoisseur, patronized a number of artists; Mercier was jealous of his own position, quarrels ensued, and in 1736 he was replaced by John Ellys. After a short period in Northhamptonshire he took lodgings on the piazza at Convent Garden from 1737 to 1739. Unable to compete with the new portraiture of Jean-Baptiste Vanloo, Ramsay, and others, Mercier originated the genre of the fancy picture, sentimentalized figures engaged chiefly in domestic occupations, intended for a wide market through engraving in mezzotint.
His first eight subjects were published by Faber in 1739. In the same year he settled in York, where he was soon patronized by leading Yorkshire families and remained in respectable practice as a portraitist until 1751, visiting Ireland in 1747 and Scotland in 1750. After a year in Portugal in 1752 he resettled in London, concentrating on fancy pictures; he exhibited two at the first exhibition of the Society of Artists in 1760. He died in London on 18 July of that year.
[Hayes, John. British Paintings of the Sixteenth through Nineteenth Centuries. The Collections of the National Gallery of Art Systematic Catalogue. Washington, D.C., 1992: 168-169.]
Waterhouse, Sir Ellis. "English Painting and France in the Eighteenth Century." Journal of the Warburg and Courtauld Institutes 15 (1952): 127-128.
Raines, Robert and John Ingamells. Philip Mercier 1689-1760. Exh. cat. City Art Gallery, York; Iveagh Bequest, Kenwood, London. London, 1969.
Ingamells, John and Robert Raines. "A Catalogue of the Paintings, Drawings and Etchings of Philip Mercier." Walpole Society 46 (1978): 1-70.
Hayes, John. British Paintings of the Sixteenth through Nineteenth Centuries. The Collections of the National Gallery of Art Systematic Catalogue. Washington, D.C., 1992: 168-169.