Jamie Dimon was born on March 13, 1956, in New York City, USA. He attended Tufts University, where he graduated with a degree in psychology and economics, and later earned an MBA from Harvard Business School. Dimon began his career in the financial sector at American Express, working under Sandy Weill, who became his mentor. Dimon followed Weill through various mergers and acquisitions, which eventually led to the creation of Citigroup.