The son of Irish immigrant Thomas Mellon [1813-1908] and his wife Sarah Jane Negley [1817-1909], Andrew W. Mellon was born in Pittsburgh. Thomas Mellon came to America in 1818 with his parents, and through his entrepreneurial skills and fortuitous investments became a very wealthy and powerful man with a career as a lawyer and later a judge, and a banker. Two of his four sons, first Andrew and then Richard B. [1858-1933], succeeded him as head of the Mellon family bank, established in 1870. Andrew played a major role in the development of the Gulf Oil Corporation, and participated in the organization of the Union Steel Company, Pittsburgh Coal Company, Koppers Gas and Coke Company and numerous other companies. In 1913 Andrew and his brother Richard established the Mellon Institute of Industrial Research in Pittsburgh as a memorial to their father; in 1967 the Institute merged with the Carnegie Institute of Technology to form Carnegie-Mellon University. In 1921 Andrew left Pittsburgh to serve as Secretary of the Treasury in Washington, a post he kept until 1932. He was Ambassador to Great Britain from 1932 until March 1933, after which he moved back to his native city. The remainder of his life was devoted to philanthropy.
Andrew W. Mellon was a keen collector of art. He bought his first painting around 1880 during a trip to Europe with Henry Clay Frick; it was the first visit abroad for them both. Thus began fifty years of collecting and the honing of Mellon's taste and eye for quality. Inspired by London's National Gallery, Mellon had the idea of turning his collection into the foundation of a National Gallery of Art in Washington. In 1930 he established The A.W. Mellon Educational and Charitable Trust, the medium through which he made his gift to the nation. In 1930-1931, with the collaboration of a consortium of the art dealers M. Knoedler & Co., P & D Colnaghi, and the Matthiesen Gallery in Berlin, Mellon entered into complicated negotiations and eventually acquired over twenty pictures being sold by the Hermitage museum in Saint Petersburg [Leningrad]. Mellon returned to Washington in 1937 for the purpose of overseeing the construction of the National Gallery of Art, but he died later the same year and thus did not live to see its opening in 1941.
In 1900 Andrew Mellon married Nora McMullen [d. 1973], a young British woman with whom he had two children, Ailsa [1901-1969] and Paul [1907-1999]. Nora had difficulty adjusting to Pittsburgh, and spent as much of the year as possible in England with their children, leading to the Mellon's estrangement and eventual divorce.
Both of Andrew Mellon's children continued in their father's tradition of art patronage. Paul served as one of the original trustees of the National Gallery of Art, overseeing its construction following his father's death, and he worked closely with its successive directors for some fifty years. Paul and his sister, Ailsa Mellon Bruce, supported the construction of the East Building of the Gallery and each became important collectors in their own right, making significant gifts of art to the Gallery over many years.