Churchill had been made Lord Churchill of Eyemouth (1682) in the Scottish peerage, Baron Churchill of Sandridge (1685), and Earl of Marlborough (1689) in the Peerage of England, all conferred by King William III. Shortly after her accession to the throne in 1702, Queen Anne made Churchill the first Duke of Marlborough and granted him the subsidiary title Marquess of Blandford.
In 1678, Churchill married Sarah Jennings (1660–1744), a courtier and influential favourite of the queen. They had seven children, of whom four daughters married into some of the most important families in Great Britain;one daughter and two sons died in infancy. Because they had no surviving sons, the dukedom was allowed by a special Act of Parliament to pass to a woman and through a woman. When the 1st Duke of Marlborough, died in 1722, his title as Lord Churchill of Eyemouth in the Scottish peerage became extinct, and the Marlborough titles passed to his eldest daughter Henrietta (1681-1733), the 2nd Duchess of Marlborough. She was married to the 2nd Earl of Godolphin and had a son who predeceased her.
When Henrietta died in 1733, the Marlborough titles passed to her nephew Charles Spencer (1706–1758), the third son of her late sister Anne (1683-1716), who had married the 3rd Earl of Sunderland in 1699. After his older brother's death in 1729, Charles Spencer had already inherited the Spencer family estates and the titles of Earl of Sunderland (1643) and Baron Spencer of Wormleighton (1603), all in the Peerage of England. Upon his maternal aunt Henrietta's death in 1733, Charles Spencer succeeded to the Marlborough family estates and titles and became the 3rd Duke. When he died in 1758, his titles passed to his eldest son George (1739–1817), who was succeeded by his eldest son George, the 5th Duke (1766–1840). In 1815, Francis Spencer (the younger son of the 4th Duke) was created Baron Churchill in the Peerage of the United Kingdom. In 1902, his grandson, the 3rd Baron Churchill, was created Viscount Churchill.
In 1817, the 5th Duke obtained permission to assume and bear the surname of Churchill in addition to his surname of Spencer, to perpetuate the name of his illustrious great-great-grandfather. At the same time he received Royal Licence to quarter the coat of arms of Churchill with his paternal arms of Spencer. The modern Dukes thus originally bore the surname "Spencer": the double-barrelled surname of "Spencer-Churchill" as used since 1817 remains in the family, though some members have preferred to style themselves "Churchill".
The 7th Duke was the paternal grandfather of the British Prime Minister Sir Winston Churchill, born at Blenheim Palace on 30 November 1874.
The present (11th) Duke is John George Vanderbilt Henry Spencer-Churchill.
After his leadership in the victory against the French in the Battle of Blenheim on 13 August 1704, the 1st Duke was honoured by Queen Anne granting him the royal manor of Woodstock, and building him a house at her expense to be called Blenheim. Construction started in 1705 and the house was completed in 1722, the year of the 1st Duke's death. Blenheim Palace has since remained in the Churchill and Spencer-Churchill family.
Dukes and Duchesses are buried in Blenheim Palace's chapel. Most other members of the Spencer-Churchill family are interred in St. Martin's parish churchyard at Bladon, a short distance from the palace.