Started at National City which would become Citibank. Got his first big break working with Aristotle Onasis, where he engineered financing for Onasis based on the future potential earnings of an asset. This allowed business leaders to make bolder bets and decisions, but focus on a shorter horizon1.
References
1.
Stoller, M. Goliath: The 100-Year War Between Monopoly Power and Democracy. (Simon & Schuster, New York, 2019).