He was imprisoned, along with his brothers William and Andrew, in Norwich in 1396. Richard II of England ordered their release from the Mayor and bailies of that city on 29 June. It appears that their imprisonment was due to violations of the truce between the Kingdoms of England and Scotland. A John Hamilton, either his brother John Hamilton of Bardowie, or uncle John Hamilton of Fingalton, was released from the Tower of London on the same date. Hamilton and his uncle seem to have found themselves guests of the English again, when at a meeting of Border commissioners at Hawdenstank on 28 October 1398, the first point of business was the release of Hamilton of Cadzow, and Hamilton of Fingalton and others in their entourage. The Hamiltons had been caught at sea by English privateers, again in violation of the truce. The English were urged to release the ship and restore their goods to them, or alternatively pay suitable recompense.
There is no record of Hamilton's death, though it is possible that he was one of the prisoner fatalities at the Battle of Homildon Hill in 1402, where a Sir John Hamilton, elder, appears on a list of captives.
John Hamilton married Janet or Jacoba Douglas, daughter of Sir James Douglas, 1st Lord Dalkeith, prior to 1388. It was thought that he had three sons by her: