Cornwallis was commissioned an ensign in the British army in 1756 and saw service in Europe in the Seven Years War. Entering Parliament in 1760, he opposed the tax measures that helped bring on the American Revolution, but when the war came he placed himself at the King’s service and was sent to America. He served under Gen. William Howe at the battle of Long Island, in the New Jersey campaigns, and at the battle of Brandywine, acquitting himself with credit in all the engagements. In 1778, Cornwallis became second in command to Sir Henry Clinton, British commander in America. Two years later Cornwallis began the fateful Carolina campaign, which led directly to the Yorktown campaign and the major British defeat that in 1781 ended the fighting. In 1786 he became Governor-General of India where he reformed the civil service and the judiciary and distinguished himself in the campaigns against Tippoo Sahib of Mysore. He was created a Marquess in 1792, returning to England in 1794. In 1798, Cornwallis was sent to Ireland as viceroy and commander in chief, and he was stern in repressing the rebellion there in the same year. He worked to achieve the Act of Union (1800), which initiated the unhappy experiment of uniting the Irish and British parliaments, but he resigned (1801) with William Pitt when George III refused to accept Catholic Emancipation. Cornwallis was then commissioned British minister plenipotentiary and helped to draw up the Treaty of Amiens (1802), which temporarily halted the war with Napoleonic France. In 1805 he was again appointed Governor-General of India, but he died only two months after taking up the position.
The present portrait shows the distinct influence of British artists active in India at this time, particularly Robert Home (1753-1834) and James Whales (1747-1795). The composition and style betrays a debt to their manner of approach which, though, at times was accustomed to a certain stiffness of form was always characterful. This can be seen in a number of the portraits that have survived executed by Whales of members of the Peshwa and Maratha courts. Cornwallis is therefore straightforwardly represented in a simple direct manner which is at once both striking and, in parts, charmingly naive in execution.