John Parker was born on 3 May 1772, the son of John Parker, 1st Lord Boringdon and his wife Teresa. He married Lady Augusta Fane on 20 June 1804, but divorced her on 14 February 1809 and married Frances Talbot on 23 August of the same year. He was created Viscount Boringdon and 1st Earl of Morley on 29 November 1815.
Downman executed a full-length portrait of 1st Earl of Morley also dated 1805 in the uniform of the Devonshire Militia, which is in the collection of the National Trust at Saltram. He exhibited a portrait of Lady Boringdon at the Royal Academy in 1806, no.466.