John Davison Rockefeller Sr. (July 8, 1839 – May 23, 1937) was an American business magnate and philanthropist. He was a co-founder of the Standard Oil Company, which dominated the oil industry and was the first great U.S. business trust. Rockefeller revolutionized the petroleum industry, and along with other key contemporary industrialists such as Andrew Carnegie, defined the structure of modern philanthropy. In 1870, he founded Standard Oil Company and actively ran it until he officially retired in 1897.

Rockefeller founded Standard Oil as an Ohio partnership with his brother William along with Henry Flagler, Jabez A. Bostwick, chemist Samuel Andrews, and a silent partner, Stephen V. Harkness. As kerosene and gasoline grew in importance, Rockefeller's wealth soared and he became the world's richest man and the first American worth more than a billion dollars, controlling 90% of all oil in the United States at his peak. Adjusting for inflation, his fortune upon his death in 1937 stood at $336 billion, accounting for more than 1.5% of the national economy, making him the richest person in US history.

Rockefeller spent the last 40 years of his life in retirement at his estate, Kykuit, in Westchester County, New York. His fortune was mainly used to create the modern systematic approach of targeted philanthropy. He was able to do this through the creation of foundations that had a major effect on medicine, education and scientific research. His foundations pioneered the development of medical research and were instrumental in the eradication of hookworm and yellow fever.

Rockefeller was also the founder of both the University of Chicago and Rockefeller University and funded the establishment of Central Philippine University in the Philippines. He was a devoted Northern Baptist and supported many church-based institutions. Rockefeller adhered to total abstinence from alcohol and tobacco throughout his life. He was a faithful congregant of the Erie Street Baptist Mission Church, where he taught Sunday school, and served as a trustee, clerk, and occasional janitor. Religion was a guiding force throughout his life, and Rockefeller believed it to be the source of his success. Rockefeller was also considered a supporter of capitalism based in a perspective of social darwinism, and is often quoted saying "The growth of a large business is merely a survival of the fittest."