Hackett, Thomas (d. 1697), deprived Church of Ireland bishop of Down and Connor, is said to have been born in England but the date and exact place of his birth and the identity of his parents are unknown. Educated at TCD, where he was a scholar in 1637, he graduated MA. He held a benefice in Cork before 1649, and Vincent Gookin (qv) and Lord Broghill (qv) certified in 1655 ‘upon personal and long knowledge of Mr Thomas Hackett, minister of the gospel’ that he had ‘been faithful to the commonwealth and a sufferer for it’ and had at that date ‘occasions of moment to be transacted in Holland with his mother-in-law about his wife's portion which may justly necessitate his longer stay in England’ (Nat. Arch., Kew, SP 63/286, 59). He was a close associate of the Cork clergyman Dr Edward Worth (qv), chief religious adviser to Henry Cromwell (qv).
Created DD of Oxford university in November 1660, he preached a sermon before the convocation of the Church of Ireland in May 1661, and about the same time was appointed dean of Cork on the recommendation of the duke of Ormond (qv). Resigning this appointment in 1662 to become rector of St Christopher's, London, 1662–3, and vicar of Cheshunt in Hertfordshire, 1662–72, he was also rector of Datchworth, Hertfordshire, 1661–72, and a chaplain-in-ordinary to Charles II from an unknown date until 1672. On the recommendation of the lord lieutenant, the earl of Essex (qv), he was appointed bishop of Down and Connor in 1672. The early years of this appointment, when he was resident in the dioceses, were unexceptionable. He made a friend of a local magnate, the earl of Conway (qv), and corresponded with Essex about diocesan affairs, especially the position of the strong presbyterian community there, a topic of concern to ecclesiastical and secular authorities alike. The bishop thought it was possible to treat with the moderate presbyterians and to divide them from extremists.
He complained in 1678 to Archbishop Sancroft of Canterbury that his banishment to Ireland agreed neither with his body nor his mind. In 1680 he mentioned his intention to travel to Bath; he does not appear to have returned to Ireland before 1694. In 1681 he received his first leave of absence, and in London in 1683 he told Sancroft that his life depended on translation to England. He warned the Irish primate, Michael Boyle (qv), of a dean and some gentleman from Ireland petitioning in England against certain practices in the Church of Ireland, including unions of dioceses; he perhaps hoped in part thus to ingratiate himself with the Irish government. A warrant was prepared in 1681 for his appointment to the privy council of Ireland, though he was presumably not sworn. He seems to have persuaded Lord Deputy Arran (qv) that his own ill health, or alternatively his wife's, prevented his return to Ireland. His persistent excuses of illness were doubtless the origin of the premature report of his death which reached Archbishop Boyle in 1685.
In 1686 the newly appointed lord lieutenant, Clarendon (qv), already in possession of a highly unfavourable report on the state of the dioceses, gave a very cool reception to Hackett's request for an extension to his licence of absence and to his suggestion of the appointment of a coadjutor or assistant; nonetheless the bishop does not appear to have returned. After the Williamite revolution the persistent and growing scandal of the neglected state of the dioceses moved the government, with encouragement from Queen Mary, to appoint a royal commission of visitation in 1693. Two prominent reform-minded bishops, William King (qv) and Anthony Dopping (qv), held hearings in Lisburn in February to April 1694, and quickly passed a sentence of deprivation on Hackett. The commissioners were appalled by the neglect and demoralisation they found in the Church of Ireland in Down and Connor, and were acutely sensitive to the opportunities such weakness provided for the presbyterians. The most serious findings were of simony, of the usurpation of the bishop's authority – mainly by a Mrs Mary Cole and by the bishop's own wife – and various instances of incontinent living and non-residence among diocesan clergy. In one instance the bishop was found to have admitted a papist to a church living in return for a renewal of his licence of absence by the earl of Tyrconnell (qv). Several clergy besides the bishop were deprived, the most senior (and the one who most persistently disputed the sentence) being Lemuel Mathews (qv), archdeacon of Dromore.
Hackett died and was buried in August 1697 in Lisburn cathedral. He was married at least twice; of the earlier marriage no more is known than appears in the document of 1655 mentioned above. He married (in London, by licence dated 1676) Catharine Whatton, daughter of John Whatton, of Raunston in Leicestershire, and his wife, Catharine Babington; both her parents were of Leicestershire gentry families. She was excommunicated by the commissioners, but was seeking absolution in 1698. Her date of death is unknown, and she was survived by her daughter and heir, Conway.