Second son of Elizabeth Campbell, duchess of Hamilton and Argyll. His older brother James having died at the age of fourteen, Douglas Douglas-Hamilton, 8th Duke of Hamilton and 5th Duke of Brandon, also inherited the title Baron Hamilton of Hameldon upon the death of his mother. He lived in Europe between 1772 and 1776 under the tutelage of Dr. John Moore. He was a patron of Moore's son, the future Sir John Moore.