Petraeus, 60, will serve as chairman of the New York firm's newly created KKR Global Institute. He was CIA director from September 2011 until last November. Before that, Petraeus served more than 37 years in the U.S. Army, where he rose to the rank of four-star general.
Petraeus served as commander of NATO forces in Afghanistan and also commanded forces in Iraq in 2007 and 2008, when violence in that country dropped following a surge in military forces.
KKR said Thursday that Petraeus will support its investment teams and portfolio companies when studying new investments, especially in new locations. The company did not detail terms of its agreement with Petraeus, but a spokeswoman said he will serve in a consultant's role.
Petraeus has a doctorate from Princeton University and has written widely on international relations, military strategy and tactics, and national security issues. He also has taught economics and international relations at the U.S. Military Academy.
Petraeus will add the new job to a couple of teaching assignments. Earlier this month, the University of Southern California announced that he will join its faculty to teach classes and mentor ROTC members.
In April, Macaulay Honors College at City University of New York named Petraeus a visiting professor for public policy starting next August. He said in a statement released by Macaulay that he was looking forward to leading a seminar on the global economic slowdown.
KKR said the global institute will help it focus on issues that can affect its global investments. Those include public policy, regulatory and technology trends. The institute also will build on KKR's push to help its portfolio companies expand globally.
KKR invests in companies and, in general, hopes to profit by selling them a few years later. KKR also has an asset management business, which invests in debt and equities, and a capital markets business, which arranges debt financing for deals and underwrites stock sales for other companies. It had $78.3 billion in assets under management as of March 31.
Shares of the company fell 5 cents to $20.06 Thursday before markets opened. But the stock has climbed more than 30 percent since closing 2012 at $15.23.