He will assist the new KKR Global Institute in assessing new opportunities, especially in parts of the world which the business does not currently invest in. The group did not detail the terms of the agreement.
Petraeus was formerly a four star general in the US army who commanded international forces in both Iraq and Afghanistan. In October last year, he resigned as CIA director following revelations of an affair with his biographer.
Since the beginning of this year, the former commander has been acquiring teaching positions around the US. Both the University of Southern California and City University of New York recently announced that Petraeus would be joining their faculty.
His extramarital relationship was publicised after its discovery by the Federal Bureau of Investigation, during a separate probe into a potential breach of classified information.