The sitter was the eldest son and heir of Timothy Shelley, of Fen Place, and his wife, Johanna Plum, of New York. He was born on 10 December 1729 in Newark, New Jersey, and married Mary White (d.1759), daughter of William White, of Horsham, West Sussex, on 22 December 1752. He died on 4 October 1790 and is buried at Warnham, West Sussex. He was succeeded by his younger brother, Bysshe Shelley (1731-1815), who was created a Baronet on 3 March 1806.
John Shelley's great-nephew was the famous poet Percy Bysshe Shelley (1792-1822).