Born about 1480, he was the eldest son of Sir John Shelley (died 3 Jan. 1526) and his wife Elizabeth (died 31 July 1513), daughter and heir of John de Michelgrove in the parish of Clapham, Sussex.
Of the judge's six brothers, one, John, became a knight of the Order of St John, and was killed in defending Rhodes against the Ottoman Turks in 1522; from another, Edward, who is variously given as second, third, or fourth son, came the baronets of Castle Goring, Sussex (created 1806), and Percy Bysshe Shelley, the poet.
From the beginning of Henry's reign he appears on commissions of the peace for Sussex and other counties; in 1517 he was autumn reader in the Inner Temple, and about the same time became one of the judges of the sheriff's court in London.
In 1520 he was appointed recorder of London, and in May 1521 was placed on the special commission of oyer and terminer to find an indictment against Edward Stafford, 3rd Duke of Buckingham.
In 1527 Shelley was raised to the bench as judge of the common pleas, and in 1529 he was sent to demand from Thomas Wolsey the surrender of York House, later Whitehall Palace.