He is Admiral Mike Mullen and 60 Minutes and CBS News correspondent David Martin spent eight days traveling with him to the frontlines of Iraq, Afghanistan and Pakistan as he prepared for this historic transition to a new president he had never even met until recently.
"He asked to see me and I went out there a couple of weeks ago and so I had about 45 or 50 minutes with the president-elect in Chicago," Mullen recalled. "It was the two of us. There was one note taker there, but it basically was one on one."
Mullen is in the middle of a two-year term as chairman, a position he was named to by President Bush. That makes him the only member of the new national security team who was not handpicked by Barack Obama.
Asked what he thinks of Obama, Mullen told Martin, "I thought he was very focused, he knew what he wanted to talk about."
"So the president-elect reaches out to you. How big a deal is that?" Martin asked.
"It's a huge deal as far as I'm concerned," Mullen replied. "I think any president, and as the commander in chief, the connection with the military is absolutely vital and so making that connection as early as possible and as solid as possible, I think is a huge deal."
Mullen will be serving a president who once called the war in Iraq "dumb" and made this promise over and over: "My first day in office I will bring the Joint Chiefs of Staff in and I will give them a new mission and that is to end this war."
To advise the new president on what that will take, Mullen flew to Iraq just before Christmas. 60 Minutes went with him as he talked with battlefield commanders and Iraqi military leaders.
From the Green Zone in Baghdad, to a forward operating base in Tikrit, to an intense on-the-run briefing at an airbase in western Iraq, it was a firsthand look at just how difficult a pullout will be.
It's not just the 140,000 troops. It's the tons of equipment and acres of command centers built up over nearly six years of war - all of it to be brought home without triggering the collapse of Iraq's government. Mullen himself once said setting a timetable for withdrawal would be dangerous.
"2009 is going to be a huge year. And at the beginning of that year the new president has said he's going to call you in and tell you…to end the war in Iraq. Is that mission impossible?" Martin asked.
"No, I don't think it's mission impossible," Mullen said. "He's said very consistently that he wants to do so responsibly. Certainly, a responsible withdrawal, a responsible ending is, I think you know a very, very possible outcome here given what I've seen transpire over the last couple of years, and literally what I saw today walking the streets of Samarra."
Two years ago it would have been impossible for Mullen to walk down the streets of Samarra, where the bombing of the Golden Mosque touched off sectarian fighting that almost tore the country apart. It's still dangerous enough to require a phalanx of armed guards, but there's a new mayor, who Mullen met and congratulated.
And shops are open on a street that was once the epicenter of Iraq's civil war. The mosque, one of the holiest sites in Iraq, is being rebuilt.
"That strikes me as sort of the perfect symbol of where we are…in Iraq," Martin remarked.
"I don't disagree with that. I think that's a pretty good …description, yeah," Mullen said.
But he also agreed that there's a lot of work still ahead.
But when we flew further north it was a different story: Admiral Mullen was supposed to take another marketplace walk in Mosul but was told that with an entourage the size of his the chance of getting hit were 100 percent, so he never left the base.
But he and his wife Deborah could still roll out the chairman's holiday USO tour, bringing a little of "home sweet home" to troops on the frontlines.