Hackston was also one of the commanders of the Covenanters who fought at the battle of Drumclog on 1 June, and again at Bothwell Bridge on 22 June 1679, where he was credited with heroically defending the bridge for up to an hour against superior forces led by the Duke of Monmouth. Having escaped from the battlefield, a reward of 10,000 merks was offered for his apprehension, obliging him to stay in hiding.