Hackston belonged to a well-connected landowning family, the Hackstons or Halkerstones of Rathillet, in the parish of
Kilmany,
Fifeshire. He was the eldest son of James Hackston and Margaret, daughter of James Falconer of Craigfoodie, and inherited his father's estate in 1670. According to a parish minister writing in 1845, "It is not known whether he was born at the family seat. The records of the kirk-session do not go back so far". There is no indication that he was religious in his youth, but attendance at a 'field preaching' led him to cast in his lot with the
Covenanters, becoming one of their most trusted leaders. In 1679, he was asked to lead the party which had resolved to assassinate
Archbishop Sharp, but declined "upon account of a difference subsisting betwixt Sharp and him in a civil process, wherein he judged himself to have been wronged by the primate, which deed he thought would give the world ground to think it was rather out of personal pique and revenge, which he professed he was free of". He agreed, however, to stand by the others and take the consequences. Accordingly, he sat at some distance from the action, while other members of the group, led by
John Balfour of Kinloch, despatched Sharp on 3 May 1679. One of the group, James Russell, later stated that one of Sharp's servants, "came to Rathillet, who was standing at a distance with his cloak about his mouth all the time on horseback, and desired him to come and cause save his life, who answered, as he meddled not with them nor desired them to take his life, so he durst not plead for him nor forbid them". After the murder Hackston fled into the west country and took part in drawing up and publishing
The Declaration and Testimony of the true Presbyterian Party in Scotland, which condemned the government's actions in religious affairs since the
Restoration. On 29 May 1679, on the day chosen to celebrate the anniversary of the King's return to the throne, a party of Covenanters, Hackston among them, rode into
Rutherglen, extinguished the bonfire in the main street and read the
Declaration publicly before affixing it to the
mercat cross. A new fire was then lit and Acts of
Parliament and the
Privy Council passed against the Covenanters since 1660 were consigned to the flames. 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. In July 1680, he reappeared as one of the armed followers who accompanied
Richard Cameron at the issuing of the
Sanquhar Declaration. At length, on 22 July 1680, he and about 60 of Cameron's followers were surprised by a body of dragoons at
Airds Moss in
Ayrshire. A skirmish ensued in which the Covenanters were worsted, and Hackston, apparently in the capacity of commander-in-chief and badly wounded, was taken prisoner and escorted to
Edinburgh. The
Privy Council instructed that: (from 1617 to 1756) and the place of Hackston's execution. Then, following a hearing before the Privy Council, at which he was indicted for the murder of Sharp, he appeared before the Justiciary and again before the Council which pronounced sentence, ordaining: The execution took place on 30 July 1680. It seems that Hackston had a strong constitution, because, despite the loss of his hands and the disembowelling, it was claimed that his heart continued to beat for some time after it was on the executioner's knife. , Fife contains one of Hackston's hands ==Monuments==