[1] His father and uncle were goldsmiths, and in 1783, the younger Nathaniel set up in business and became jeweller to members of the royal family and courtiers.
[1][2] The couple lived richly, with a townhouse in Pall Mall and a seaside villa by Benjamin Bond-Hopkins near Ramsgate.
[1] They had several daughters and one son,[1] Nathaniel Newman Jefferys (1788–1873), later of Chepstow and Southampton and in 1817 a Master extraordinary in the Court of Chancery.
[1][5] In Parliament, Jefferys supported the Prince of Wales (his leading customer, the future George IV) against the Pitt ministry.
[1] In 1797 he went bankrupt though his customers' failure to pay their bills; a subsequent attempt to restart with his father-in-law's support was unsuccessful.