John D. Rockefeller, Sr.
The company Rockefeller started at age 23, Standard Oil, came to hold a virtual monopoly on the American oil industry. He maintained control of Standard Oil until its eventual break-up by the U.S. government. The company was so successful that through its dissolution, Rockefeller became America’s first billionaire. Rockefeller was also known for his establishment of charitable foundations and academic institutions, including the University of Chicago, the Rockefeller Institute for Medical Research, the General Education Board and the Rockefeller Foundation.