Andrew Mellon was born on March 24, 1855, in Pittsburgh, Pennsylvania, to Thomas Mellon and Sarah Jane Negley. Thomas Mellon spent most of his life as a judge, but had established himself as a banker. Young Andrew Mellon observed his father's financial dealings with his clients, many of whom were Republican politicians and notable industrialists. After completing his secondary schooling, Andrew Mellon attended the Western University of Pennsylvania (University of Pittsburgh) but left three months before graduation in 1872 to begin his own construction company. Mellon's father loaned him money with interest to establish the company. Andrew Mellon repaid his father and saw success in his first venture and later sold his company in 1874, predicting a decline in the industry. Mellon returned to his family and began working at the family bank, T. Mellon & Sons, with his father.

Mellon proved to be a good banker, expanding the bank through strategic investments, and made his brother Richard Mellon a partner in 1887. Industrialist Henry Clay Frick and Mellon established Pittsburgh's Union Trust Company, of which Mellon become president in 1889. By 1890, Thomas Mellon had made Andrew Mellon virtual owner of the Mellon Properties. Mellon continued investing in several industries, including small oil companies which he sold to Rockefeller's Standard Oil Company. He also invested in aluminum manufacturing. As Mellon's wealth grew, he began to indulge in expensive art work, leading to the eventual development of the National Gallery of Art.

Mellon married Nora Mary McMullen in 1900, daughter of a wealthy English brewery family. Immediately after his marriage, Mellon obsessively pursued his industrial investments. He helped nurture the Gulf Oil Corporation and helped merge United Steel with the U.S. Steel Corporation. By 1902, T. Mellon & Sons had become Mellon National Bank, a multi-bank holding company. Mellon began to support Republican politicians with his enormous wealth, but during this time, his obsessive love for wealth led to his divorce in 1912, after the couple had two children. Following his divorce, Mellon continued his business ventures and became a dominant officer in more than 60 corporations, including Alcoa, Koppers Industries, and Mellon-Stuart Company. Mellon's business savvy extended his reach into the development of several landmarks, including the RCA Building, the Panama Canal, the George Washington Bridge, and several buildings overseas.

Mellon's continued interest in the Republican Party earned him the position of Secretary of the Treasury under Warren G. Harding. Mellon resigned from his corporate duties with a fortune of $2 billion. Mellon's term began in 1921, during which time he lobbied Congress to reduce taxes and worked to successfully reduce the national debt which was incurred from World War I. Mellon reduced the government budget by $3.5 billion within the first three years of his term, according to the U.S. Treasury. Mellon authored The Mellon Plan (Revenue Act of 1924), which reduced taxes for the wealthy individuals and large corporations. The plan burdened the middle and lower class, assisting the wealthy like himself, with tax relief. Besides providing tax cuts for the wealthy, he supported the development of corporate America's wealth from the stock market. Mellon believed that the wealth from the upper classes would "trickle down" to the lower classes, causing many of his legislations to benefit the rich over the poor. Mellon's popularity skyrocketed and he was accredited with helping America's middle class increase their wealth. However, Mellon's reinvestment and anti-tax attitude led to inflation which helped cause the poverty observed during The Great Depression. Many citizens blamed him for their poverty resulting from the stock market crash causing them to lose their wealth in investments. At the end of his term as Secretary of the Treasury, Mellon was appointed United State Ambassador to Great Britain for one year, after which he retired.

A year after Mellon left his government office, the Department of Justice launched an investigation alleging that Mellon falsified tax information in 1931 and they sought to acquire over $3 million in penalties. Andrew Mellon's legislation centered on the wealthy was contrasted greatly during the latter part of his life when he became a devoted philanthropist. Mellon developed the Mellon Institute of Industrial Research at the University of Pittsburgh to improve industrial processes. Mellon also continued to expand his art collection, expanding his personal gallery rapidly. Mellon bought over thirty paintings from the Soviet Union (now Russia) for an estimated $8 million according to The National Gallery of Art. By 1927, Mellon planned to donate his collection to the nation, opening the National Gallery of Art. Mellon died in Southampton, New York, in 1937 during the architectural design of the museum.

After Mellon's death, his estate settled the tax fraud case for a sum of $668,000 to prevent any further problems with the government. Later, in the early 1960s, the Mellon Institute of Industrial Research merged with the Carnegie Institute of Technology to become Carnegie Mellon University. The building now houses both science and technology research projects to help the growth of man kind. Carnegie Mellon is now a leading research center with campuses all over the world and is one of the most selective private universities in the country.