Pinkney, William, 1764–1822, American political leader and diplomat, b. Annapolis, Md. Admitted to the bar in 1786, he soon became prominent in state politics. In 1796 he was sent to England as a commissioner to adjust maritime claims, remaining until 1804. Two years later he was sent with James Monroe on a special mission to England to deal with impressment and reparations for ship seizures. Pinkney remained as minister to England (1807–11), but was unsuccessful in settling difficulties between the two countries. He was U.S. Attorney General (1811–14) and fought in the War of 1812, being wounded at Bladensburg (1814). After serving as a U.S. Congressman (1815–16), he was minister to Russia (1816–18). After his return he practiced law, gaining a considerable reputation as a constitutional lawyer; he appeared before the U.S. Supreme Court as counsel for the Bank of the United States in McCulloch v. Maryland. He also served (1819–22) in the U.S. Senate.
See biography by his nephew, W. Pinkney (1853, repr. 1969); H. H. Hagan, Eight Great American Lawyers (1923).