John D. Rockefeller

Two months before his high school graduation, history's first recorded billionaire, John D. Rockefeller, Sr., dropped out to take business courses at Folsom Mercantile College. He founded the Standard Oil Company in 1870, made his billions before the company was broken up by the government for being a monopoly, and spent his last 40 years giving away his riches, primarily to causes related to health and education. This high school dropout helped millions get a good education.