Churchill, John Winston Spencer (1822–83), 7th duke of Marlborough and lord lieutenant of Ireland (1876–80), was born 2 June 1822 at Garboldisham Hall, Norfolk, eldest son of George Spencer Churchill (1793–1857), 6th duke, and his wife Lady Jane (1798–1844), daughter of George Stewart, 8th earl of Galloway. Educated at Eton (1834–9) and Oriel College, Oxford, he became conservative MP for Woodstock (1844–5, 1847–57), and succeeded to the dukedom in 1857. He was appointed privy counsellor 10 July 1866 and was lord president of the council 1867–8.
In 1874 he declined the viceroyalty of Ireland but accepted it two years later; he was appointed 28 November and sworn in 12 December 1876. From the beginning he cultivated popular opinion, made clear his conciliatory intentions towards Ireland, and attempted to implement a policy of constructive unionism. Although his tenure saw no major reforms, he was a popular viceroy, generally seen as even-handed and progressive by moderate nationalists, although some protestants complained of his favouritism towards catholics. He patronised Irish manufactures and tourism, espoused popular causes such as religious toleration in the north and an end to coercion, and in 1878 supported government aid to enable small farmers to buy their holdings. He took a particular interest in reforming education, where he saw a legitimate Irish grievance. Recognising the importance of education to the catholic clergy, he consulted them regularly and displayed a strong willingness to meet their demands at secondary and university levels. He worked closely on the issue with Sir Michael Hicks Beach (qv), his chief secretary, who was mainly responsible for producing the intermediate education act (1878). This provided grants for secondary schools based on their public examination results, which allowed for the indirect state subsidisation of catholic schools, and was largely welcomed by catholic clergy. Marlborough also played a major part in forwarding the university education act (1879), providing for the creation of the Royal University of Ireland, which had the power to award degrees to students of the Catholic University and made provision for limited state support for that university. However, the measure fell short of the clergy's hopes and Marlborough's ambitions, and he almost resigned over the cabinet's lack of support for a more advanced measure.
On these issues he was greatly assisted by his second son Randolph (1849–95), who acted as his unofficial private secretary. The period was an important one in Randolph's political development: he built up a large circle of friends in Irish academic and administrative life, was an active member of the Castle administration, and accompanied his father on political tours. In a speech in England in 1877, which caused some embarrassment for the duke, Randolph criticised the misgovernment of past administrations and the neglect of the current one. He also published a pamphlet, Intermediate education in Ireland (1878), criticising the poor provision of secondary education and the waste and mismanagement in the administration of educational endowments in Ireland.
In 1843 Marlborough married Lady Frances Anne Emily Vane Tempest (1822–99), eldest daughter of the 3rd marquess of Londonderry (qv). The duchess of Marlborough played an active public role during his viceroyalty, particularly in charitable initiatives. She cultivated a network of Irish contacts among liberal landlords and the catholic clergy, and her popularity was a major asset to the duke. She recognised the importance of journalists in promoting her husband's image and paid them considerable attention: during Castle functions she often enquired ‘Have the press been fed?’ (Robins, 136). With the onset of severe agricultural depression in autumn 1879, she set up a famine fund in December and collected £135,000 for the relief of distress; Lord Randolph was a hard-working secretary to the project. Although her efforts were widely praised, the disposal of the funds was criticised by some groups, particularly by nationalists, who had raised the rival ‘Mansion House’ fund.
As the controversy over the relief fund continued and the rise of the home rule movement polarised politics, the duke of Marlborough's relations with nationalists deteriorated, and after the fall of the conservative government in May 1880 he left Dublin in an atmosphere of some bitterness. By now disenchanted with conciliating nationalist opinion, he made several calls in the house of lords for strong measures to be taken against Irish political and agrarian agitation. He died suddenly in London 5 July 1883, and was buried at Blenheim. He was succeeded as duke by his eldest son, George Charles Spencer Churchill (1844–92).