In 1703 he purchased the position of Colonel of the 3rd the Kings Own regiment, a position he held until 1732. He also acquired that year the estates of Baramount and Killaghy in County Kilkenny and became Member of Parliament for Newtownards in the Irish Parliament. During the War of the Spanish Succession, Carpenter was appointed Quartermaster and General of Cavalry in the Anglo-Dutch force led by Charles, 3rd Earl of Peterborough sent to Spain in 1704 to support Archduke Charles, Austrian candidate for King of Spain. In 1706 James Stanhope was appointed English Minister in Spain; at Almansa in 1707, Carpenter's repeated cavalry charges mitigated an Allied defeat by saving the guns and baggage train. Stanhope replaced Peterborough as military commander in 1708; Carpenter took part in the victory at Almenara in 1710 but a few months later was badly wounded and taken prisoner with many others including Stanhope at Brihuega. This ended the war in Spain in favour of Phillip V; Carpenter was later exchanged and promoted to Lieutenant-General. Stanhope was a prominent Whig and when George I succeeded Queen Anne in 1714, Carpenter was nominated Envoy to Emperor Charles VI. Before taking this position the Jacobite rising of 1715 broke out and Carpenter was put in charge of government forces in Northern England. He prevented the Jacobites seizing Newcastle, forcing them into the Battle of Preston where they were attacked by troops under Major-General Charles Wills. The first assaults were repulsed but the Jacobites were surrounded by Wills and Carpenter and surrendered on terms. Wills and Carpenter served together in Spain and had quarrelled at some point; Carpenter later claimed Wills was taking all the credit for Preston and challenged him to a duel which was prevented by mutual friends. Carpenter was returned as Member of Parliament (MP) for Whitchurch in Hampshire at the 1715 general election. He served as Governor of Menorca from 1716 to 1718 and Commander-in-Chief, North Britain (sic) from 1716 to 1724. He was created Baron Carpenter, "of Killaghy in the County of Kilkenny" in the Peerage of Ireland on 29 May 1719. In December 1722 he was elected MP for Westminster after the Westminster results of the 1722 general election were declared void. He did not stand at the 1727 general election. Carpenter died on 10 February 1732 a few months after his wife and was buried in the church of Owslebury in Hampshire.