He was born in 1616, the eldest son of John Cornewall and Mary Barneby, and was baptised at Eye, Herefordshire on 14 July 1616.

[1] During the First English Civil War, he served on the Royalist side under Sir Henry Lingen, though he later claimed to have done so only to defend himself and his neighbours from the depredations of cavalier soldiers.

Edward Harley attested that Cornewall was forced to participate in an assault on Stokesay Castle and to sit on a royalist grand jury.

[2] For this support of the cause of King Charles, he was fined £222 (equivalent to £39,859 in 2023[3]) by the victorious Parliamentarians on 1 July 1647.

The couple had nine children:[1] Humphrey Cornwall died and was buried at Ludlow on 7 July 1688.