Coningsby was an ardent supporter of the revolution of 1688, and opposed the Jacobite faction. Coningsby accompanied William III to Ireland, and was present at the battle of the Boyne where the King was injured. He was appointed joint receiver and Paymaster-General of the forces employed in the reduction of Ireland, and from 1690 to 1692 he acted as the junior of the three Lord Justices. He established a network of friends and allies in Ireland, notably Sir John Hely, the Chief Baron of the Irish Exchequer, who had married his sister-in-law Meliora Gorges. It is said that he helped arrange the treaty of Limerick. His political opponents accused him of having used his position for profiteering by the embezzlement of stores, the appropriation of the estates of rebels, the sale of pardons, and dealings in illicit trade.