His father was the eldest son of Lady Mary Jones and Lt.Col. John Chichester, who was MP for Dungannon and fought in the English Civil War. After his grandfather's death, his grandmother married Col. Christopher Copley of Wadworth.[2] His maternal grandparents were Sarah (née Loftus) Itchingham and John Itchingham of Dunbrody, County Wexford.[4]
Sometime before 1682, he married Lady Barbara Boyle, a daughter of Roger Boyle, 1st Earl of Orrery and Lady Margaret Howard (a daughter of the 2nd Earl of Suffolk). Lady Donegall died on 16 November 1682 without surviving issue.
Lord Donegall died on 10 April 1706 and was succeeded by his eldest son, Arthur. His widow, the dowager Lady Donegall, died on 15 June 1743. After the 4th Earl died without issue in 1757, the title passed to his nephew (the 3rd Earl's grandson), Arthur, who was created Baron Fisherwick in the Peerage of Great Britain in 1790 and Marquess of Donegall in the Peerage of Ireland on 4 July 1791.[4]
^ abG.E. Cokayne; with Vicary Gibbs, H.A. Doubleday, Geoffrey H. White, Duncan Warrand and Lord Howard de Walden, editors, The Complete Peerage of England, Scotland, Ireland, Great Britain and the United Kingdom, Extant, Extinct or Dormant, new ed., 13 volumes in 14 (1910-1959; reprint in 6 volumes, Gloucester: Alan Sutton Publishing, 2000), volume IV, pp. 390-391.