Swynnerton belonged to the cadet branch of a distinguished Staffordshire family, being the grandson of Sir John Swynnerton† of Hilton, who was himself the younger brother of Roger, first Lord Swynnerton of Swynnerton (d.1338). Sir John had built up a substantial estate, which included the manors of Hilton and Welton, as well as land and rents in the Staffordshire villages of Essington, Wyrley, Pillaton and Penkridge, and the area around Ticknall in Derbyshire. The seneschalsy of Cannock forest came to him through marriage, and passed, together with the rest of his property, to his son, Sir John. The latter made further additions to his inheritance, most notably the purchase of the manor of Essington, and like his father before him earned a considerable reputation as a soldier, sheriff and local commissioner.
Swynnerton’s appointment as escheator of Staffordshire in November 1401, his return to Parliament while still in office and the award of an annuity of five marks made to him for life from the Derbyshire estates of the duchy of Lancaster at some point before 1412 suggest that he was known and recognized for his loyalty to the house of Lancaster. Yet this did not prevent the temporary confiscation of his land in Cannock forest, for in 1403 the Crown finally took steps to recover the rents which it had been claiming from the reign of Edward III.
