The sitter, baptised on 20 November 1721, was the younger son of Sir Robert Bankes Jenkinson, 4th Bt. and M.P. for the County of Oxford, and Catherine, third daughter of Sir Thomas Dashwood, Bt. He succeeded as Baronet after the death of his unmarried elder brother, Sir Robert, in 1766. Romney's portrait shows Sir Bankes two or three years before his death on 22 July 1789. Since he had also never married, the baronetcy passed to his cousin, Sir Charles Jenkinson, 1st Lord Hawkesbury, who in 1796 was advanced by George III to the Earldom of Liverpool.