Lord Newbattle was a volunteer in the Dutch War of 1673. He succeeded his father in the earldom in 1675. Sworn a Privy Counsellor in January 1686, he was removed by James II in September. Lothian supported the Glorious Revolution and sat in the Convention of Estates of Scotland. He was appointed Lord Justice General of Scotland in 1689, holding the office until his death, and was re-appointed a privy counsellor by William III in 1690. In the same year, he succeeded his uncle Charles as Earl of Ancram.