In 1990, on the heels of the collapse of Drexel Burnham Lambert, he co-founded the private equity firm Apollo Global Management with Leon Black, Drexel's managing Director, head of the Mergers & Acquisitions Group, and co-head of the Corporate Finance Department; John Hannan, Drexel's former co-director of international finance; Craig Cogut, a Lawyer who worked with Drexel's high-yield division in Los Angeles; Arthur Bilger, the former head of the Drexel's corporate Finance department; and Marc Rowan, Josh Harris and Michael Gross, all of whom worked under Black in the mergers and acquisitions department. In 1997, he co-founded Ares Management with former Apollo Global Management co-worker John H. Kissick and Bennett Rosenthal, who joined the group from the global leveraged Finance group at Merrill Lynch.