The Goldman Sachs CEO didn't take the typical route to finance. He actually started out as a lawyer. He got his law degree from Harvard at age 24, then took a job as an associate at law firm Donovan Leisure.

"I was as provincial as you could be, albeit from Brooklyn, the province of Brooklyn," Blankfein told William Cohen at Fortune Magazine.

At the time, he was a heavy smoker and occasional gambler. Despite the fact that he was on the partner track at the firm, he decided to switch to investment banking, joining J. Aron at the age of 27.