William Douglas was the son of Sir Archibald Douglas (died 1333) and Beatrice de Lindsay, the daughter of Sir Alexander de Lindsay of Crawford, South Lanarkshire. He was the nephew of “Sir James the Good”, the trusted deputy of King Robert I of Scotland (Robert the Bruce). From the time of his father’s death at the Battle of Halidon Hill, Douglas is described as being a ward of his kinsman and godfather, William Douglas, Knight of Liddesdale, and was educated in France. In 1342, under pressure from Liddesdale, his uncle Hugh the Dull resigned the Lordship of Douglas to him, though Liddesdale rapaciously administered his estates while it was in his ward-ship, and assumed direct ownership of some of the Douglas territories.
Douglas returned to Scotland, upon reaching his majority in 1348, and immediately started to put his house in order. In 1346-47 following the Battle of Neville’s Cross, King David II, and other nobility, including Liddesdale, were held captive by the English. Edward Baliol used the opportunity to ravage the whole of the south of Scotland. Douglas gathered his men and drove the English out from his ancestral lands of Douglasdale. Douglas went in the style of his uncle, the Good Sir James, and for the following few years waged guerrilla war against the English in the Ettrick Forest and Jedforests.
Douglas next became one of the commissioners to negotiate with the English for the release of David II of Scotland.
In 1353, Edward Baliol was ensconced at Buittle in his ancestral territories in Galloway. Douglas led a raid there to eject him due to Baliol’s forfeiture of those lands that had been made over to Sir James Douglas in 1324. Following this raid, returning through the Forest, Douglas came across Liddesdale hunting on what Douglas viewed as his desmesne. This was the match that lit the fuse of years of resentment over Liddesdale’s assumption of the Douglas patrimony, notwithstanding Liddesdale’s murder of Sir Alexander Ramsay of Dalhousie which John of Fordun gives as a reason for the enmity between the men. Liddesdale, once in high standing with the Crown, had fallen into disfavour following his murder of Ramsay and another Knight, Sir David de Barclay. Douglas set upon Liddesdale and killed him. In February 1354, William of Douglas received a new charter from King David bestowing all the lands held by his uncle Sir James, his father Sir Archibald, and Liddesdale itself.
In 1355 the truce with England expired and Douglas with the Earl of Dunbar and March, whose lands had been ravaged, decided to take Norham Castle in retaliation. One of Douglas’ captains, Sir William Ramsay of Dalhousie, was instructed to despoil the lands around Norham and burn the town in an effort to entice the garrison out to battle. Ramsay did so and the English under the castle’s constable, Sir Thomas Grey of Heaton and Lord Dacre, gave chase. Douglas and March meanwhile were encamped seven miles away in woodland to the south of Duns, when Ramsay had reached them. The English pursuers were ambushed by the Scots force, and completely overwhelmed. Following this Battle of Nesbit Moor, Douglas and March joined with the Earl of Angus in making an assault upon Berwick, but the Scots had to retire from there before the advancing army of Edward III. King Edward laid waste to the Lothians in an event that would be known as the “Burnt Candlemas”. His supply lines were overstretched, and following the sinking of his fleet, and the Scots scorched earth policy, Edward had to turn homewards, but not before being ambushed and nearly taken by Lord Douglas’s men outside Melrose. Following Edward’s retreat into England, Douglas arranged a truce with William de Bohun, 1st Earl of Northampton that would last until Michaelmas.
He also arranged a Safe conduct to visit the captive King David. Following this Douglas crossed with a large following to France and took up arms with Jean le Bon against Edward of Woodstock, the Black Prince. Douglas was present at the Battle of Poitiers where he was knighted by the French King. Douglas fought in the King’s own Battle, but when the fight seemed over Douglas was dragged by his men from the melee. Froissart states that “… the Earl Douglas of Scotland, who fought a season valiantly, but when he saw the discomfiture he departed and saved himself; for in no wise would he be taken by the Englishmen, he would rather there be slain”. After the defeat there Douglas escaped, but left a number of his men either slain or captive, including his first cousin latterly the 3rd Earl of Douglas, Archibald the Grim.
Douglas returned to Scotland by mid Autumn, and was involved in peace negotiations with the English, one aspect of the treaty was the creation of March Wardens of which Douglas was one. Under the auspice of this office, Douglas seized Hermitage Castle in Liddesdale from the English in response to their depredations on Eskdale. Douglas was part of the parliament that met at Berwick in 1357, which finalised the release of King David through the Treaty of Berwick, Douglas himself being one of the securities for his release.
Douglas was created Earl of Douglas on 26 January 1358. To reflect his new-found status, he built Tantallon Castle, a Medieval castle surrounded by a curtain wall. The castle became the home of Douglas’ sister-in-law and mistress, Margaret Stewart, 4th Countess of Angus, the mother of his illegitimate son, George Douglas, who would later be created Earl of Angus by the right of his mother.
In 1364, Douglas joined King David II in seeking a treaty with England that would have written off Scotland’s debt to England in return for depriving his nephew, Robert the Steward, formerly an ally of Douglas, of the succession. King Edward III’s son, Lionel of Antwerp, would have taken the Scottish throne, although the independence of Scotland was to be guaranteed, and a special clause was to be provided for the restoration of the English estates of the Douglas family.
The plan never succeeded, and on the accession of Robert the Steward as King Robert II, Douglas was nevertheless reconciled and appointed Justiciar South of the Forth in 1372. The last years of Douglas’ life were spent in making and repelling border raids. He died at Douglas on 1 May 1384.