Ball, John Thomas (1815–98), lord chancellor of Ireland and MP, was born 24 July 1815 in Portmarnock, Co. Dublin, eldest of six sons and four daughters of Maj. Benjamin Marcus Ball and Elizabeth Ball (née Feltus). He was educated at Dr Smith's school, Rutland Square, Dublin, and TCD, where he was president of the College Historical Society, and graduated BA (1836) with gold medal, LLB (1841), and LLD (1844). Called to the bar (1840) and QC (1854), he was elected a bencher of the King's Inns (1863) and appointed queen's advocate in Ireland (1865). He practised mainly in the ecclesiastical courts but also in the courts of probate, common law, and equity, and on circuit where he was a crown prosecutor; he was engaged in many important cases, including the Yelverton trial and the Egmont estates case of the 1860s.
In 1862 Primate Marcus Beresford (qv) appointed him vicar-general of the province of Armagh. In response to increasing demands for the disestablishment of the Church of Ireland, Ball stood for parliament (1865) as a liberal for Dublin University. He advocated reform of the Irish church to remove the threat of disestablishment: ‘let improvement commence from within; so shall you avert innovation from without’ (J. T. Ball, 20). His views were not endorsed by the electors and he was defeated, but in 1867 Disraeli appointed him a member of the royal commission to enquire into the property and organisation of the Church of Ireland. Opposing liberal moves towards disestablishment, he was elected conservative MP for Dublin University (1868–75) and during 1868 was successively appointed solicitor general, attorney general, and privy councillor for Ireland. Serving as an MP during a period of significant legislative change, he took a prominent role in all debates concerning Ireland, earning a reputation for his oratorical skills. As a member of the conservative opposition (1868–74), he vigorously opposed the Irish church bill introduced by Gladstone (1869), arguing that religion consecrates civil government and that in Ireland, since both the Roman Catholic and presbyterian churches had repudiated state involvement, they should receive generous endowment while the established church should retain its status. His influence, both inside and outside parliament, contributed to the softening of the severity of the original bill and his contribution was recognised by the award (1870) of an hon. DCL (Oxon.). After the disestablishment of the church, he was an important figure in its reconstruction: he helped to draft its new constitution, served as assessor to the general synod of the Church of Ireland, and was a member of the Church Representative Body; he subsequently published The reformed Church of Ireland (1537–1886) (1886; revised and updated ed., 1890).
In 1870 he supported the land bill introduced by Gladstone to regulate more equitably the relations between landlord and tenant, and his proposed amendments were later incorporated into the act. Opposing the University Education (Ireland) Bill (1873), which proposed the absorption of all colleges into a national non-sectarian university, he argued that the bill did not serve educational needs and would result in the demise of great educational institutions, and that its proposals were inimical to the intellectual culture of Ireland and indifferent to Irish sympathies. When the conservatives regained power (1874), Ball was reappointed attorney general but resigned his seat (1875) to serve as lord chancellor (1875–80). His health seriously impaired, he waived his claim to resume the chancellorship when the conservatives returned to power (1885) and subsequently took little part in public affairs. Other positions held by Ball included the offices of chancellor of the dioceses of Armagh and Dublin, vice-chancellor of Dublin University (1880–95), senator of the Royal University, and member of the boards of national and intermediate education.
From his student days, he had contributed to Dublin University Magazine; admired for his scholarship, he also published Ballot considered in connection with the extension of the franchise (1872) and Historical review of the legislative systems operative in Ireland from the invasion of Henry the second to the union (1888). He died 17 March 1898 at his home, Taney House, Dundrum, Co. Dublin, and was buried in Mount Jerome cemetery, Dublin. His portrait by Walter Osborne (qv) is in King's Inns, Dublin. He married (1852) Catherine (d. 1887), daughter of the Rev. C. R. Elrington (qv), regius professor of divinity in Dublin University; they had three sons, the youngest of whom was the antiquarian and author Francis Elrington Ball (qv).