Stephen Feinberg is an American billionaire businessman who currently serves as the 36th United States Deputy Secretary of Defense, a position he has held since March 2025. He is best known as the co-founder of Cerberus Capital Management, a massive private equity firm he started in 1992 with just $10 million that now manages over $60 billion in assets. A major Republican donor, Feinberg previously served as chair of the President's Intelligence Advisory Board during the first Trump administration, though his business dealings have sparked conflict-of-interest concerns. Known for his secretive nature, he once controversially joked about "killing" employees who leaked photos to the press, and he has candidly admitted that private equity executives are "way overpaid." After graduating from Princeton in 1982, he built his career in finance before being nominated by President-elect Trump in December 2024 to his current defense role.