Former Chairman and CEO of Morgan Stanley, John J. Mack, is getting back into the workforce.  KKR hired him as one of its most prominent senior advisers, yet.  Typically, PE firms like KKR bring on a notable former executive as a senior adviser to provide consulting services to portfolio companies.  They also can attract new investors and introduce new deals. In addition to Mr. Mack, KKR's present roster of advisers include: Arun Sarin, former CEO of the Vodafone Group, and Ford Fraker, former U.S. ambassador to Saudi Arabia. John Mack Wall Street Background. Mack last served as Morgan Stanley’s chairman. He began his career at the investment bank as a bond trader, and quickly rose through the ranks before being ousted in a power struggle in 2001.  He went to Credit Suisse until 2005, at which time he returned to M. Stanley - receiving a standing ovation on the trading floor. Thereafter, he rebuilt the firm after years of tumbling morale.  Among his signal achievements was restoring Morgan Stanley’s trading operations - though he failed to pull back before the financial crisis.  He led efforts to secure a $9 billion lifeline for the firm from the Mitsubishi UFJ Financial Group of Japan during the market turmoil. Mr. Mack also serves on the boards of several nonprofit organizations - including New York-Presbyterian Hospital and the Bloomberg Family Foundation.

"John Mack is a great leader who we believe will add enormous value to K.K.R.’s investors, partners and our portfolio." -- Henry Kravis, firm’s co-founder and co-CEO.

KKR's ties to Morgan Stanley go back a time - MS has a long history of advising KKR on deals - the first was the $4.25 billion purchase of Safeway in 1986.  The investment bank advised KKR on 28 deals other deals, since then."  [Dealbook, 3/27/12]