He appears to have been the son of John Saunders, a pastel-painter of merit, who practised at Norwich, Stourbridge in Worcestershire, and elsewhere.
[1] Sanders was a student at the Royal Academy in 1769, and earned a silver medal in 1770.
During these years he was resident in Great Ormond Street, and in 1775 appears in the catalogue of the Royal Academy as John Saunders, junior.
A portrait of Judith, countess of Radnor (at Longford Castle), painted in 1821, is a very good example of his work.
He is mentioned by Madame d'Arblay in her Journal as painting a portrait of Princess Charlotte of Wales.