King was ill with tuberculosis when he was nominated as Pierce's running mate in 1852, and had gone to Cuba for his health at the time of the inauguration in March of 1853. King had served several terms in the Senate and was the President pro tempore when his illness forced him to resign on December 20, 1852. King was allowed to take the oath of the office of vice-president in Cuba on March 24, 1853 by an act of Congress, giving him the distinction of being the only nationally-elected official to take the oath of office on foreign soil. He never made it to Washington, dying within two days of his return to his native Alabama, on April 18, 1853.
Much has been made of the fact that King lived with James Buchanan for 15 years in Washington, D.C. There is no clear documentary evidence that they had a homosexual relationship, but the nieces of the two men destroyed all correspondence between the two, fueling speculation. Andrew Jackson is said to have called King "Miss Nancy" and "Aunt Fancy." Aaron Venable Brown, who served as Governor of Tennessee from 1845-1847 and was a delegate to the Democratic Convention of 1852, is said to have referred to the housemates as "Buchanan and his wife." Apparently, Buchanan never heard Brown's characterization or was the forgiving type, because Brown was appointed Postmaster General during Buchanan's presidency.
A peculiar spinoff of the ambigous relationship of Buchanan and King can be found in a collection of oil paintings called All the Presidents' Girls by British artist Annie Kevans, wherein William King is the only male among the thirty portraits of Presidential mistresses.