born March 24, 1855, Pittsburgh, Pa., U.S.
died Aug. 26, 1937, Southampton, N.Y.
U.S. financier.
He joined his father's banking house in 1874 and through the next three decades built up a financial empire by supplying capital for corporations in industries such as aluminum, steel, and oil. He helped found the Aluminum Co. of America ( Alcoa ) and the Gulf Oil Corp. , and he joined Henry Clay Frick to found Union Steel Co. and Union Trust Co. By the early 1920s he was one of the richest men in the U.S. As secretary of the Treasury (192132) he persuaded Congress to lower taxes in order to encourage business expansion. He was praised for the economic boom of the 1920s but criticized during the Great Depression , and in 1932 he resigned to serve as ambassador to England. A noted art collector and philanthropist, Mellon donated an extensive art collection and $15 million to establish the National Gallery of Art .