Royalist and statesman. Grandson of John Maitland of Thirlestane (c.1545 - 1595). Born at Lennoxlove House (then Lethington), near Haddington. He married the Countess of Dysart. He was captured at the Battle of Worcester (1650), imprisoned in the Tower of London and his estates were forfeited. They were restored under King Charles II (1630-85), who made him Secretary of State, a position in which he exercised enormous power, regarded as the 'uncrowned King of Scotland'. He was the 'L' in Charles' so-called 'CABAL' administration, running Scotland without hindrance, despite corruption and intrigue, resisting the reproach of his rivals. Although having the reputation of being unscrupulous and crude, he was created Duke of Lauderdale in 1672, having inherited the Earldom of the same name from his father in 1645. When not in London or Edinburgh, he made his home at Thirlestane Castle, which he rebuilt and extended. He also refurbished Lennoxlove, then Lethington, the family home in East Lothian.
He compromised with the Covenanters while maintaining the ultimate authority of the King, but this strategy failed leading to the Battles of Drumclog and Bothwell Brig (1679) and his fall from power. He died at Tunbridge Wells (Kent) and the Dukedom ceased with him. He is buried in the crypt below the Lauderdale Aisle in St Mary's Church, Haddington.