The sitter was the eldest son of James, 2nd Marquess of Hamilton, and Lady Anne Cunningham, daughter of the Earl of Glencairn. The Hamilton family was among the most powerful in Scotland, having next claim to the Scottish throne after the descendants of James VI.
In 1623, Hamilton accompanied Prince Charles, future King Charles I, and the Duke of Buckingham to Madrid in an unsuccessful attempt to negotiate a marriage between Charles and the Spanish Infanta. Hamilton struck up a close friendship with the Prince during this trip, and on their return to England was made a Gentleman of the Bedchamber. On Buckingham's assassination in 1628, Hamilton was appointed Master of the Horse. In 1631, he commanded a large force of English and Scottish troops sent to fight for Gustavus Adolphus against the Catholic Hapsburgs in Germany. He was appointed to the Privy Council in 1633 and became the King's chief adviser in Scottish secular affairs. Hamilton's invasion of England at the head of a large Scottish force in aid of the King, during the Second Civil War in 1648, ended in disaster and his own execution at Westminster on 9 March 1649.
Hamilton was a patron of the arts and built up a large collection of paintings, a number of which were eventually bought by the Archduke Leopold Wilhelm and are now in the Kunsthistoriches Museum, Vienna.
This portrait derives from a full-length portrait that excludes the horse and groom, now in the Liechtenstein collection. Other three-quarter-length portraits of this type are at Gosford House and Blair Castle.