Born in Bladensburg, Maryland, on November 8, 1772, Wirt was educated in private schools, and for a time worked as a private tutor. He studied law and was admitted to the bar in 1792. He practiced law privately for a few years, became clerk of the Virginia House of Delegates in 1800, and in 1802 was chancellor of the Eastern District of Virginia. In 1807, President Jefferson appointed him prosecuting attorney in the trial of Aaron Burr. President Monroe appointed Wirt Attorney General in 1817. He also served in the cabinet of President John Quincy Adams until 1829. At that time he moved to Baltimore and practiced law until his death on February 18, 1834.
Wirt wrote several books during his life, including Letters of a British Spy (1803) and Sketches of the Life and Character of Patrick Henry (1817).
King was born in Newport, Rhode Island. He studied under Edward Savage in New York City, and then in London under Benjamin West from 1805 to 1812. Returning to America, he spent several years in Philadelphia and Baltimore before settling in the District of Columbia where he made his home until his death. King is especially noted for his portraits of American Indians. In 1857 King painted Attorney General Wirt's portrait.