He and Lord Inchiquin commanded the forces which defeated the Irish irregular army at the Battle of Liscarroll on 3 September 1642, thereby preserving the Protestant interest in southern Ireland for the remainder of the decade.

He then applied to the King, in December, for consent to bring his regiment to serve him in England, and landed his men near Chester the following February.

The Commonwealth fined him £1631 sterling and he then went abroad, returning to Ireland at the request of the government, dated 2 January 1651.

On 22 February 1660, he was made Custos Rotulorum of County Cork and of Waterford, and on 19 March 1660, he was appointed one of the Commissioners for the settlement of Ireland following the King's declaration to that effect on 30 November 1659.

Lord Burlington (as he was usually known for short from 1664 onwards), along with several other noblemen and Bishops of the Church of Ireland, were opposed to the attempts of King James II of England in regard to the restoration of Roman Catholicism and petitioned the King on 17 November 1688 to call a parliament "regular and free in all its circumstances".

Following the arrival of William of Orange in England, King James removed to Ireland where he called a parliament in 1689, which passed an act of attainder against certain Protestants deemed disloyal to the king,[2] and confiscated their estates, among whom was the Earl of Burlington (who was also Earl of Cork).