Immigrated to England (1749) and studied enamel and miniature painting in London. Won prize for a profile portrait of George III to be used on coinage (1761). Naturalized (1762). Enamel-painter to the King and miniature painter to the Queen (1764). Founding member of Royal Academy (1769); contributed several royal portraits to Academy’s exhibitions and helped established pension fund (1775). Widely esteemed as a person as well as an artist.
Born at Tübingen. Married Barbara Marsden (1763); had issue.