Hamilton's new patron was the new Lord of Douglas, George Douglas, 4th Earl of Angus, the head of the "Red line" of the House of Douglas, and a supporter of the King. Hamilton married first, Lady Euphemia Graham, daughter of Patrick Graham, de jure Earl of Strathearn and Euphemia Stewart, Countess of Strathearn and widow of Archibald Douglas, 5th Earl of Douglas. They had a daughter: He married secondly, Princess Mary Stewart of Scotland, daughter of James II of Scotland, and widow of Thomas Boyd, Earl of Arran. By Princess Mary, Hamilton had three children:  Illegitimate children included Sir Patrick Hamilton of Kincavil, father of Master Patrick Hamilton, burnt for heresy in 1528 and a Protestant martyr. Lord Hamilton also had a daughter who married Sir John MacFarlane, 11th chief of Clan MacFarlane. John Hamilton of Broomhill (d. c. 1550), another illegitimate child of James, 1st Lord Hamilton, was by Janet Calderwood. In 1512 John's birth was legitimised. His grandson, James Hamilton, notably served as Sheriff of Perthshire, and his descendants became the Lords Belhaven and Stenton. Another illegitimate child by Janet Calderwood was David Hamilton, Bishop of Argyll and commendator of Dryburgh Abbey.