son of James, 1st Lord Hamilton, and of Mary, daughter of James II of Scotland; he was created earl of Arran in 1503 on the occasion of the marriage of James IV to Margaret Tudor.

Arran commanded a naval expedition against England in 1513 but failed lamentably and returned to find his rival, the earl of Angus, supreme at court. He therefore allied with the duke of Albany, regent for James V, and was himself from 1517 to 1520 one of six vice-regents. But in the feuds of these years he had no fixed allegiance. His most spectacular encounter was the fierce fight between the Hamiltons and the Douglases in the streets of Edinburgh, known as “Cleanse the Causeway” (1520). When James V freed himself from the power of Angus in 1528, Arran joined him at Stirling.