Arthur Lee trained in medicine at Edinburgh and practiced briefly in Virginia before turning to law and political writing in London. Admitted to the bar in 1770, he represented colonial grievances through essays, pamphlets and correspondence. Massachusetts appointed him its agent, and in 1775 Congress made him a confidential correspondent in Britain, drawing on his access to political information.

Congress sent Lee into European diplomacy in 1776. He joined Benjamin Franklin and Silas Deane as a commissioner in France and undertook missions seeking assistance from Spain and Prussia. In February 1778 he signed the treaties of alliance and commerce with France. His relations with fellow commissioners deteriorated over their handling of supplies, accounts and appointments. The resulting accusations became a major dispute within Congress and contributed to the recall of American representatives.

Lee returned to Virginia in 1780 and served in the House of Delegates. He represented the state in the Confederation Congress from 1782 to 1784, then joined the federal Board of Treasury in 1785, remaining until the new constitutional government replaced it in 1789. His writings had also condemned slavery. He unsuccessfully sought election to the United States House in 1790 and a Senate vacancy in 1792. Retiring at Lansdowne in Urbanna, he died that December, after serving both the revolutionary diplomatic establishment and the Confederation's financial administration.