John Nixon was the son of Robert Nixon, a successful Irish merchant. With his brother Richard, he too developed a mercantile career, living and working at Basinghall Street, near Guildhall Yard in the City. He was a special juryman at the Guildhall and a Captain of the Guildhall Volunteers. Yet at the same time, he moved in leading artistic and fashionable circles, acting as honorary secretary of the Beefsteak Club and producing a number of landscape paintings, caricatures and illustrations.

Nixon exhibited at the Royal Academy of Arts between 1781 and 1813, while another of his brothers, the Rev Robert Nixon (1759-1837), was an honorary exhibitor between 1790 and 1808. As curate at Foots Cray, Kent, Robert played host to J M W Turner, who painted his first oil while staying with him in 1793, and gave him his first lessons in landscape painting. He also received lessons in figure painting from Stephen Rigaud. In 1798, Robert accompanied Turner and Rigaud on a sketching tour of Kent. Yet another brother, James, was a miniature painter.

John Nixon combined business and pleasure by both trading and sketching on the frequent tours that he made to Ireland in the 1780s and 1790s; he was accompanied on one such Irish trip by topographer and caricaturist, Captain Francis Grose (1791), and in turn went with Thomas Rowlandson to Bath (1792).

As a result of extensive travels, across Britain and on the Continent (1783-84; 1802 and 1804), Nixon became a topographical illustrator; his drawings were included in Seats of the Nobility and Gentry (1779-86) and he illustrated Thomas Pennant’s Journey from London to the Isle of Wight (1801) and a Guide to Watering Places (1803). He also exhibited a set of illustrations to Laurence Sterne’s Tristram Shandy at the Royal Academy (1786). Throughout the period, he drew popular caricature prints, often published by William Holland and usually satirising social preoccupations, such as A Country Dance.

Nixon was a member of the set of Elizabeth Craven (Lady Craven), Margravine of Ansbach at Brandenburg House, Hammersmith, and proved a notable amateur actor in its theatrical productions.