Leighton, Sir Ellis (Elisha) (d. 1685), politician and courtier, was of Scottish extraction, youngest son of Alexander Leighton, presbyterian divine; his mother's surname was Mears or Means, and his parents had married by 1611. Christened Elisha, he later preferred ‘Ellis’. His elder brother Robert (d. 1684) later served as archbishop of Glasgow. Leighton's early life remains obscure. He took the royalist side during the English civil war and rose to the rank of colonel. He later joined the exiled court on the Continent, becoming acquainted with Col. Richard Talbot (qv) and Sir John Berkeley (qv). In 1652 he converted to catholicism after a bout of severe mental illness, though Gilbert Burnet later suggested that this was simply to curry favour, Leighton in his view being ‘a very immoral man, both lewd, false and ambitious’ (Burnet, History, i). Originally an associate of George Villiers, duke of Buckingham, he became secretary to James, duke of York (qv), and was knighted in April 1659. Leighton was apparently good company, if little else, ‘his judgment being nothing at all, but his wit most absolute’ (Pepys, Diary, v, 300). He held a number of minor offices after the restoration, receiving the degree of LLD from Cambridge (19 May 1665) on the king's recommendation. At one point he was secretary of the Royal African Company.
On 21 April 1670 Leighton was appointed chief secretary for Ireland under Berkeley, now Baron Berkeley of Stratton, with whom he had a close political relationship. Indeed, as secretary, Leighton concerned himself with maintaining good relationships between Berkeley and key figures at court such as Buckingham (who supported Leighton) and Henry Bennet, earl of Arlington. Leighton proved energetic in his role, though the opportunity for profit contributed to this and he also practised at the Irish bar. A hard worker, he effectively monopolised viceregal business. He agreed with Berkeley's policy of independence from Irish interest groups, and proved willing to tackle outstanding political issues, such as the persistent difficulty of finance (the priority for Berkeley's government) and preparations for a possible parliament in 1670. The assistance of Archbishop Oliver Plunkett (qv) in dealing with the threat posed by tories contributed to the good relations the titular primate enjoyed with the administration. While fiscal rather than religious policy was the key to the appointment of Berkeley and Leighton, they were undoubtedly well disposed towards catholicism; Plunkett claimed that Leighton was a catholic, and at one point Leighton requested Plunkett's personal ministrations while on his sickbed.
However, his fortunes were inextricably linked to those of Berkeley. He was employed on numerous occasions to defend the Irish government in England, and the enmity of Richard Jones (qv), earl of Ranelagh, towards Berkeley also extended to Leighton, though Ranelagh later sought to turn Berkeley against him. Yet, while efficient and well regarded in some quarters, Leighton proved exceptionally corrupt, at one point procuring a grant of lands for Berkeley under his own name. He specialised in such brokering, and profited handsomely from a variety of sources, but complaints over his conduct were emerging from at least May 1671. From late 1671 his influence was undermined by the growing influence over Berkeley of Alice Hamilton, Lady Clanbrassil, and as Berkeley was rendered redundant by the onset of Ranelagh's undertaking, Leighton concentrated on lining his pockets. He became embroiled in a disastrous attempt by Berkeley to exert greater control over Dublin corporation in April 1672. Leighton himself displayed an authoritarian attitude towards the corporation, being installed in the potentially lucrative post of recorder of Dublin in place of Sir William Davies, a nephew of the lord chancellor, Michael Boyle (qv). The ensuing controversy contributed to Berkeley's recall. Sir Henry Ford (qv) replaced Leighton as chief secretary on 5 August 1672. The new viceroy, Arthur Capel (qv), earl of Essex, reversed Leighton's appointment as recorder and reinstalled Davies 20 September 1672, a decision backed unanimously by the corporation.
After this, Leighton had no further dealings with Ireland. He accompanied Berkeley to France in 1675, but was imprisoned in London after being accused of seeking bribes. He escaped to France to avoid prosecution, but was later implicated in the ‘popish plot’, being detained at Dover in 1678 ‘not only as a man named by Mr Oates, but upon some other iniquity’ (Ormond MSS, iv). Leighton died on 9 January 1685, and was buried in Horsted Keynes, Sussex. His career seemingly became a byword for corruption; in February 1687 the then viceroy Richard Talbot, now earl of Tyrconnell, blamed him for Berkeley's recall, and offended his newly appointed secretary Thomas Sheridan (qv) by telling him ‘to avoid corruption, and not imitate Sir Ellis Leighton’ (Stuart MSS, vi, 12). Virtually nothing is known of his family, but he had at least one daughter, Mary.