Plunket, William Conyngham (1828–97), 4th Baron Plunket , archbishop of Dublin, was born 26 August 1828 at 30 Upper Fitzwilliam Street, Dublin, the eldest son of the six sons and eight daughters of John Plunket, QC, and his wife, Charlotte, third daughter of Charles Kendal Bushe (qv), lord chief justice of Ireland. He was educated at a Dublin day school and Seaforth Rectory, near Liverpool, before entering Cheltenham College in 1842. He was a distinguished student, winning a silver medal (classics, 1845), being elected head of school, and in 1847 co-founding and editing a school paper entitled Tirocinia, or the Cheltenham Collegian. The pressures of his busy school life induced a nervous breakdown, however, and while recuperating at home he read religious texts which redirected his early political ambitions in favour of the church.
Plunket entered TCD in May 1847 and graduated successively BA (1853), MA (1864), BD, and DD (both 1877). His delicate health delayed his ordination as deacon until 1857, after which he became chaplain and private secretary to his uncle Thomas, second Baron Plunket (qv), bishop of Tuam, Killala, and Achonry. He was ordained priest and served as rector of the united parishes of Kilmoyland and Cummer in the diocese of Tuam (1858–64). While in the west he formed a close friendship with Alexander Dallas (qv) and became a committed evangelist, joining Dallas's Irish Church Missions Society and establishing the West Connaught Endowment Fund. In 1863 he married Anne (see below), only daughter of Sir Benjamin Lee Guinness (qv) and his wife, Elizabeth. Sir Benjamin was then sponsoring the restoration of St Patrick's cathedral, and Plunket was subsequently appointed treasurer (1864) and served as precentor (1869–76) of the cathedral. He actively opposed the disestablishment of the Church of Ireland, and although participating in the reorganisation that followed disestablishment, his proposed revisions to the prayer book were rejected because of their overt evangelicalism. Plunket succeeded to the peerage in 1871, and was later bishop of Meath (1876–84) and dean of Christ Church, Dublin (1884–7). In 1884 he was elected archbishop of the united dioceses of Dublin, Glendalough, and Kildare, an office he held until his death.
Plunket's episcopal career was marked by an ardent evangelicalism, though he became well known for a capacity for compromise and for the temperance and tolerance of his religious outlook. He was particularly concerned with continental protestantism, championing the cause of the reformed churches in Spain, Portugal, and Italy. He travelled often to continental Europe, and was appointed president and chairman of the Italian Reform Association (1886). In 1891 he caused much controversy when he ordained his private chaplain, Andrew Cassels, for the Lusitanian church in Portugal, and his support for Spanish protestantism (notably his consecration of Cabrera as bishop in 1894) attracted much censure from English high-church clergymen. Nevertheless, the ecclesiastical authorities maintained a general oversight of the Iberian protestant bodies until 1963, when the Spanish reformed church and the Lusitanian church were received into full communion with the Church of Ireland.
Plunket's other main area of endeavour was religious education in Irish national schools, and it was largely through his efforts that the Kildare Place training schools became the Church of Ireland Training College for teachers. He was a senator of the RUI, and in 1888 was awarded an honorary LLD by Cambridge in recognition of his work as an educationalist. In 1895 he was nominated a member of the board of national education. He wrote poems and hymns throughout his life, some of which were published in the Irish Metropolitan Magazine (under the pseudonym ‘UUP’, in 1857), Irish Readings, Irish Penny Readings (1879–85), The Church Hymnal, and Lyra Hibernica Sacra (1878).
Plunket died 1 April 1897 at his home, 16 St Stephen's Green, Dublin. A statue by Hamo Thorneycroft was unveiled on 16 April 1901 and stands in Kildare Place. Collections of his papers are held in TCD, the Bodleian Library, Oxford, and the National Library of Wales, Aberystwyth.
His wife Anne (‘Annie’) Lee Guinness (1839–89), philanthropist, was born in 1839, the only daughter of Sir Benjamin Lee Guinness. During her father's restoration of St Patrick's cathedral she became actively involved in alleviating the poverty and sickness endemic in the surrounding area. She sponsored Bible readings and basic medical provision, which expanded to become St Patrick's nursing home (1876), an important training centre for Church of Ireland nurses. On 11 June 1863 she married William Conyngham Plunket, with whom she had four daughters and two sons. Plunket supported his wife's work at St Patrick's, and she assisted in many of his educational projects, notably the establishment of the Irish Clergy Daughters’ School (Earlsfort Terrace, Dublin) and the extension of Alexandra College. She suffered for much of her life from a degenerative illness and died 8 November 1889 at their home, Old Connaught House, Bray. She was buried in the Guinness family vault at Mount Jerome cemetery, and commemorated in St Patrick's cathedral by a series of stained-glass windows depicting the works of Dorcas (or Tabitha), helper of the poor.