Gen. Martin Dempsey to Be Obama Administration's Chairman of the Joint Chiefs of Staff

A surprising selection after his recent appointment as Army's top officer.

May 25, 2011 -- Army Chief of Staff Gen. Martin Dempsey is the Obama administration's choice to become the new chairman of the Joint Chiefs of Staff, succeeding Adm. Mike Mullen, who will retire Oct. 1, ABC News has learned.

An administration official confirmed the White House's surprise selection of the veteran officer who became the Army's top officer last month.

Dempsey's selection finishes out the realignment of the Obama administration's Pentagon team brought on by the retirements of Mullen and Defense Secretary Robert Gates. Leon Panetta, director of the Central Intelligence Agency, will replace Gates as defense secretary when he leaves his post June 30.

Dempsey's name had emerged in recent weeks as a top candidate to succeed Mullen as the chances of Marine Gen. James Cartwright seemed to fade. Cartwright had long been assumed to be the front-runner since Bob Woodward's book, "Obama's Wars," characterized him as President Obama's "favorite general."

But Cartwright's chances seemed to lessen on criticism of his management style and a Pentagon investigation into claims of misconduct with a young female aide. The Department of Defense's inspector general cleared Cartwright of having an improper relationship with the aide, but faulted his handling of an incident in which the aide had become drunk and fallen asleep in the hotel room in which he was working while security staff was stationed outside the room.

During a meeting with Obama Saturday, a Defense official told ABC News, Cartwright was told that he was no longer a candidate to be the president's top military adviser. Neither Gates nor Mullen endorsed Cartwright to be the new Joint Chiefs chairman, the official said.

Dempsey served two combat tours in Iraq where he commanded the 1st Armored Division shortly after the 2003 invasion and later ran the U.S. effort to train Iraqi security forces. Dempsey also served as the acting commander of U.S. Central Command, which has responsibility for U.S. military affairs in the Middle East.

Prior to assuming the job as Army chief of staff in early April, Dempsey spent two years heading the Army's Training and Doctrine Command.

The career armor officer is a member of the West Point graduating class of 1974 where Gen. David Petraeus was a classmate.

Now the top military commander in Afghanistan, Petraeus will also play a role in the Obama administration's shuffle of national security players. Petraeus is slated to replace Panetta as the new CIA director in September.