He will need all those skills if, as expected, President Obama nominates him to be chairman of the Joint Chiefs of Staff, a move that could come as early as Monday.

As the military?s highest-ranking officer and a crucial member of the president?s revamped national security team, General Dempsey would face a complex and consequential set of challenges against the backdrop of both rapid change abroad and intensive political pressures at home: how fast to withdraw from Afghanistan, how to reshape the military and how to cope with an era of fiscal austerity.

If confirmed by the Senate, General Dempsey, currently the Army chief, would become the president?s senior military adviser, working alongside Leon E. Panetta, the Central Intelligence Agency director, who is in line to become defense secretary when Robert M. Gates retires in late June, and Gen. David H. Petraeus, who will take over from Mr. Panetta at the C.I.A.

Officials said the high opinion Mr. Gates has of General Dempsey ? one shared by the departing chairman, Adm. Mike Mullen ? was a significant factor in shaping Mr. Obama?s decision. The president initially favored Gen. James E. Cartwright, the current vice chairman, before questions of personnel management and command style pushed him out of the running.

General Dempsey carries no visible political baggage and has no vocal critics across the armed forces. The only sour notes sounded at word of his nomination came from those who regret his departure from the post of Army chief. The exhausted ground force, they said, needs someone like General Dempsey who not only can employ the Army in combat, but also knows how to rebuild it.

Of the senior commanders to emerge from the wars in Iraq and Afghanistan, General Dempsey is known as among the least self-aggrandizing. That, too, was said to have been an attractive trait to a White House that is seeking to avoid public drama and that has felt cornered at times by strong egos within the war cabinet during policy battles, in particular over Afghanistan and Pakistan.

Military commanders and Mr. Obama ? who as a presidential candidate ran against the Bush administration?s war in Iraq ? have struggled to build strong ties. And in some ways, the decision to pass over General Cartwright in favor of General Dempsey exposed lingering fault lines in the administration, despite what White House, Pentagon and military officials agree is a smoother working relationship today than during the review of Afghanistan policy.

Both Mr. Gates and Admiral Mullen were frustrated, even angered, by General Cartwright?s consultations with the White House in which he offered alternative options for troop numbers in Afghanistan, according to Pentagon and military officials.

General Cartwright?s supporters say the vice chairman was only fulfilling his required duties of giving his best professional advice to the president. But some senior Pentagon and military officials said that General Cartwright had erred in not keeping Mr. Gates and Admiral Mullen fully aware of the separate options he had discussed with the commander in chief.

A West Point graduate of 1974, General Dempsey, 59, earned a master?s degree from Duke University ? in English, a subject he later taught West Point cadets.

And he can sing. Several thousand video scouts have found, seen and heard General Dempsey channel his inner Frank Sinatra in an acceptable rendition of ?New York, New York,? delivered in Army dress uniform.

As a one-star brigadier general, he was sent to Baghdad in 2003 to stabilize the Iraqi capital region in command of an Army division ? historically a task reserved for a two-star major general.

As a festering resistance exploded into full-fledged rebellion, he fashioned a complicated counteroffensive that mixed deadly attacks, political agility, media management and the infusion of cash into ravaged neighborhoods to suppress the Shiite revolt. And he did it so successfully that Barry R. McCaffrey, a retired general, labeled him the best combat division commander of the past decade. (Congress subsequently approved a second star.)