Southwell, Edward (1671–1730), chief secretary for Ireland and MP, was born 4 September 1671, sole surviving son of Sir Robert Southwell (qv), diplomat and politician, of Kings Weston, Gloucestershire, England, and Kinsale, Co. Cork, and his wife Elizabeth Dering. He went to school in London before entering Lincoln's Inn (1686), but he never pursued a legal career. He instead entered (1687) Merton College, Oxford, but his university career was short-lived as his father persuaded him to leave Oxford in 1688 after the attempts of King James II (qv) to interfere in the affairs of the university. Despite this Southwell was noted for his intellect, and was elected to the Royal Society aged 21 (1692).
Both Southwells were early adherents to William of Orange (qv), and the young Edward joined William's retinue (1688) before accompanying him to Ireland (1690). He also attended the allied conference at The Hague (1691). The Southwell family had made their fortune in the plantation of Munster, and enjoyed extensive estates in Co. Cork, including the town of Kinsale. His father held various public offices in Ireland, and Edward followed him into the Irish bureaucracy. In 1692 he was made joint prothonotary of common pleas in Ireland, and in the following year he was appointed to one of his father's old offices as a clerk of the privy council in London, where he quickly established a reputation for diligence. He also embarked on a parliamentary career, entering the Irish house of commons for the family borough at Kinsale (1692), which he represented till his death, apart from a relatively brief interlude (1703–10) when he sat for TCD.
His career prospered in the years immediately following his father's death (1702). First, he succeeded to his father's largely sinecure but prestigious office as secretary of state for Ireland, with a salary of £350 a year. He concluded an advantageous marriage in October 1703 to Elizabeth (d. 1710), daughter and heir of Vere Essex Cromwell, 4th earl of Ardglass, which brought with it estates in Co. Down, including the borough of Downpatrick. Also in 1703, he was appointed chief secretary by the 2nd duke of Ormond (qv), an appointment that owed much to the long association between the two families. His father had served the 1st duke of Ormond (qv) in several capacities, although never as chief secretary. Southwell served Ormond in both his viceroyalties (1703–7, 1710–14). These were years of intense party conflict on both sides of the Irish Sea, but Southwell, although nominally a tory, was not a particularly partisan figure. He delegated much of the management of the Irish parliament to others, and instead concentrated on his administrative duties. As well as sitting in the Irish house of commons, he also sat at Westminster, representing Rye (1702–7), Tregony (1710–13), and Preston (1713–15).
After the Hanoverian succession Southwell remained in parliament as MP for Kinsale, but spent most of his time in England, either at Kings Weston, where he had built a new house designed by Sir John Vanbrugh in 1710, or in London. He continued to oversee his Irish affairs at Kinsale and Downpatrick from afar, managing his political interests and estates, and building noted charity schools in both towns. Southwell remained secretary of state for Ireland, and kept abreast of Irish affairs through correspondence with several members of the Irish administration, including Marmaduke Coghill (qv), Archbishop William King (qv), and Thomas Medlycott, on whose behalf he acted in both personal and political matters. His role as clerk of the privy council meant that he wielded some influence at Whitehall, while his long experience of government, on both sides of the Irish Sea, made him an indispensable point of contact for Irish officials when they travelled to London. He was engaged in a semi-official capacity to manage Irish bills at the privy council. He rarely ventured into active political engagement, but did publish a pamphlet in 1724 during the ‘Wood's halfpence’ crisis. Entitled A letter from Dublin to William Wood, it criticised the introduction of the halfpence, pointing out that the many Irish landowners and officeholders resident in England would not be willing to receive their rents or salaries in the coinage. This was an issue of particular concern to Southwell, who, according to Archbishop King had ‘received out of Ireland at least £60,000 since the revolution’ for his various offices (quoted in HIP, vi, 307).
Southwell suffered greatly from gout, and his movements in his final years were hindered by injuries suffered in a road accident. He died on 4 December 1730, and was buried at Kings Weston. His second wife, Anne (née Blaithwaite) (m. 1716), survived him. His eldest surviving son, Edward (1705–55), MP for Downpatrick 1727–55, succeeded him as secretary of state for Ireland, and as clerk of the privy council.
There is a mezzotint portrait of Edward Southwell by J. Smith, after Kneller, in the NGI. He left a very extensive archive, which is scattered across a number of institutions, including the BL, TCD, the NLI, the PRONI, the Henry E. Huntington Library in San Marino, California, and the Beinecke Library in Yale, and has proved an invaluable resource for historians of early eighteenth-century Ireland. The size of his archive reflects the reputation of Southwell as a conscientious, diligent administrator.