John Stanley was the second son of Sir William de Stanley of Stourton and Alice Massey of Timperley, Cheshire, and grandson of John de Stanley and Emma Lathom of Lathom, Lancashire.[1] Stanley's father was Master-Forester of the Forest of Wirral, notorious for his repressive activities. Both Stanley and his older brother, William (who succeeded their father as Master-Forester), were involved in criminal cases which charged them with a forced entry in 1369 and in the murder of Thomas Clotton in 1376.[2] Conviction for the murder of Clotton resulted in Stanley being declared an outlaw. However, he was already distinguishing himself in military service in the French wars, and he was pardoned in 1378 at the insistence of his commander, Sir Thomas Trivet.[3]

In 1385 he married Isabel Lathom, heir to the extensive lands of Sir Thomas Lathom in south-west Lancashire. The marriage took place despite the opposition of John of Gaunt and gave Stanley the sort of wealth and financial security he could never have hoped to have had as the younger son in his own family.[4] Stanley had four sons, John, Henry, Thomas and Ralph as well as two daughters.[5] The year 1386 saw his first appointment in Ireland as deputy to Robert de Vere, Duke of Ireland.This occurred because of the insurrection created by the friction between Sir Philip de Courtenay, the then English Lieutenant of Ireland, and his appointed governor James Butler, 3rd Earl of Ormond. Stanley led an expedituion to Ireland on behalf of de Vere and King Richard II to quell it. He was accompanied by Bishop Alexander de Balscot of Meath and Sir Robert Crull.[6] Butler joined them upon their arrival in Ireland. Because of the success of the expedition, Stanley was appointed to the position of Lieutenant of Ireland, Alexander to chancellor, Crull to treasurer, and Butler to his old position as governor.[7] In 1389, Richard II appointed him justiciar of Ireland, a post he held until 1391. He was heavily involved in Richard's first expedition to Ireland in 1394–1395.[8] Throughout the 1390s he was involved in placating possible rebellion in Cheshire.[9] Between 1396 and 1398 he served as captain of Roxburgh. Stanley took part in Richard II's expedition to Ireland in 1399. However, on his return to England, Stanley, who had long proved adept at political manouevring, turned his back on Richard and submitted to Henry IV of England.[10]