James Graham inherited the earldom of Montrose from his father in 1626. He was educated at St. Andrews University where he became inspired by classical tales of military glory in writers such as Caesar, Xenophon and Lucan. In November 1629, he married Magdalene Carnegie, daughter of Lord Carnegie of Kinnaird. After the birth of his first two sons, Montrose went to France and Italy to complete his education, which included a period at the French military academy at Angers.
He returned to Scotland in 1637 and became active in the revolt against the imposition of Archbishop Laud's prayer book on the Scottish Kirk. Montrose signed the National Covenant in 1638, and sat in the Glasgow Assembly, which abolished episcopacy and established presbyterian church government in Scotland. The King's representative, the Marquis of Hamilton, noted Montrose's assertiveness and enthusiasm, but regarded it as vanity.
Montrose gained his first military experience leading Covenanter troops in the First Bishops' War. He drove the Royalist Marquis of Huntly out of Aberdeen in March 1639 and campaigned against Huntly's clan, the Gordons. But in June, Huntly's son, Viscount Aboyne, sailed into Aberdeen harbour in one of the King's warships and trained his guns on the town. Surrounded by hostile clansmen, Montrose withdrew to gather stronger forces. He returned three weeks later with artillery and bombarded Aberdeen from the Brig o' Dee until Aboyne and the Gordons fled the city.
After the signing of the Pacification of Berwick, Montrose came into conflict with Archibald Campbell, Earl of Argyll, suspecting him of trying to usurp the power of the King in Scotland for his own ends. He also distrusted the Marquis of Hamilton, who appeared to be in league with Argyll. Montrose drew up a secret agreement with like-minded Covenanters known as the Cumbernauld Bond. Adherents undertook to defend the true principles of the Covenant against the machinations of Argyll and his supporters. Some suspected that Montrose had become a Royalist, but he had the honour of leading the first regiment of Covenanters across the River Tweed when the Scots invaded England in the Second Bishops' War (August 1640).
When the war was over, Montrose's criticisms of Argyll and his intercepted correspondence with King Charles resulted in his arrest on charges of conspiracy against the ruling Committee of Estates. In June 1641, he was imprisoned in Edinburgh Castle. When King Charles visited Scotland to finalise the treaty with England, Montrose demanded an open trial. Anxious to maintain their new alliance, neither the King nor the Estates would agree to this, but Montrose was released on bail in November 1641. He then retired from public life until the outbreak of the Civil Wars when he attempted to rally Scottish support for the King. Montrose opposed the Solemn League and Covenant, which secured an alliance between Scotland and the English Parliamentarians, and joined King Charles at Oxford in 1643. His loyalty to the King and the Royalist cause was passionate and unwavering throughout the rest of his career.
When Lord Leven's Covenanter army invaded England in 1644, the King appointed Montrose his Lieutenant-General in Scotland. Montrose planned to start a war against the Covenanters north of the border that would distract their forces in England, but no Royalist troops could be spared for the venture. In July 1644, a small band of Irish Confederates, led by Alasdair MacColla MacDonald, landed on the west coast of Scotland. They were sent by the Earl of Antrim, who had promised to supply King Charles with Irish troops. MacColla's band marched into the Highlands, terrorising the Covenanting Campbell clan as they went. Montrose located MacColla at Blair Atholl where he raised his standard as the King's Deputy on 30 August 1644. With MacColla's Irishmen and a motley band of clansmen as the nucleus of his army, Montrose began a spectacular Royalist campaign against the Covenanters in the Highlands. He defeated Lord Elcho at Tippermuir in September 1644 then captured and plundered Aberdeen. King Charles created him Marquis of Montrose and Earl of Kincardine in November 1644. The Covenanters put a price on his head, dead or alive.
Early in 1645, Montrose led a guerrilla campaign against the Campbells and their chief, the Marquis of Argyll. He struck deep into their home territory and broke the power of the Campbells in the Highlands at the battle of Inverlochy in February 1645. According to plan, Covenanter regiments were withdrawn from Lord Leven's army in England and returned to Scotland to deal with Montrose, thus weakening Leven in the field and undermining Covenanter political influence in London. After plundering Dundee in April 1645, Montrose was pursued back into the Highlands by Major-General Baillie. Constantly outwitting the Covenanters, he defeated Colonel Hurry at Auldearn in May 1645 and Baillie at Alford in June. In August 1645, Montrose achieved his greatest victory when he defeated Baillie and the Covenanter Committee of War headed by Argyll at the battle of Kilsyth, which left him for a short time master of Scotland.
Montrose's victories in Scotland kept up the morale of the Royalists in England, and the King's main strategic objective after the defeat at Naseby was to join forces with him. When Montrose moved into the Lowlands, however, his troops began to desert. He was defeated by superior Covenanter forces under David Leslie at Philliphaugh in September 1645 and his followers were massacred. Montrose remained in Scotland for another year but he was unable to pose a serious threat to the Covenanters again. In July 1646, King Charles, having surrendered himself to the Covenanters, ordered Montrose to cease hostilities. Montrose sailed into exile on 3 September 1646.
An account of his victories, written in Latin by George Wishart, made Montrose a hero throughout Europe. He was offered an appointment as Lieutenant-General in the French army; the Emperor Ferdinand III awarded him the rank of Field Marshall. But Montrose remained devoted to the service of King Charles. He was enraged when the King was executed in January 1649. Swearing vengeance, he immediately transferred his loyalty to Charles II, who was proclaimed King of Scots in February 1649. Charles appointed Montrose his Captain-General in Scotland and authorised him to negotiate for military aid with European powers. Montrose travelled through Germany, Poland and Scandinavia attempting to raise forces for the King.
To Montrose's dismay, Charles also entered into negotiations with the Covenanters. When talks broke down in May 1649, Charles attempted to coerce the Covenanters by ordering Montrose to take control of Scotland by military force. Montrose sent a small force of German and Danish mercenaries as an advance guard to occupy the Orkneys in September 1649 and joined them with reinforcements in March 1650. By the time Montrose landed on the Scottish mainland, Charles had reopened negotiations with the Covenanters. Charles wrote to Montrose ordering him to disarm, but the orders never reached him. The Covenanters moved swiftly against him. Montrose was defeated at the battle of Carbisdale by Colonel Strachan in April 1650. A few days later, Charles disavowed Montrose under the terms of the Treaty of Breda.
Montrose escaped into the mountains after Carbisdale. He fled to Aardvreck Castle on Loch Assynt where he was betrayed to the Covenanters by Neil MacLeod, Laird of Assynt. Montrose was taken to Edinburgh and led through the streets in a cart driven by the hangman. Already under sentence of death for his campaign of 1644-5, Montrose was hanged at the Mercat Cross on 21 May 1650, protesting to the last that he was a true Covenanter as well as a loyal subject.
Montrose's head was fixed on a spike at the Tolbooth in Edinburgh, his legs and arms were fixed to the gates of Stirling, Glasgow, Perth and Aberdeen. His dismembered body was buried in Edinburgh, but Lady Jean Napier had it secretly disinterred. The heart was removed, embalmed, placed in a casket, and sent to Montrose's exiled son as a symbol of loyalty and martyrdom. After the Restoration in 1660, Montrose's embalmed heart and bones were buried at St Giles' Cathedral, Edinburgh, with fourteen noblemen bearing the coffin.
Montrose's few lyrics are sparks struck off from a gallant and chivalrous life of action.