– White House Chief of Staff Denis McDonough was ready to vent.

“I’ve had too much humble pie,” he fumed, striding into a top aide’s West Wing office. “That was the last slice. I’m full.”

McDonough had just finished another hand-holding meeting with health care advocates anxious over the disastrous rollout of the health care law. For weeks, President Obama and White House officials had been apologizing for and promising fixes to a faulty website and an unmet promise to insurance holders that they could keep their policies.

McDonough’s message: It was time to change tactics, quit lamenting the problems and start emphasizing the benefits of the health care overhaul.

Center of the maelstrom

When Obama assembled his second-term team his new chief of staff promptly put his energetic stamp on things. He increased White House outreach to lawmakers, worked to rebuild relations with the Cabinet and stepped up contacts with business leaders.

Ten months later, the native of Stillwater, Minn., is trying to manage one of the roughest patches in Obama’s presidency as the White House labors to explain how the president got blindsided by the problematic enrollment launch of his health care law. As the president’s gatekeeper, McDonough is at the center of the maelstrom, charged with deciding what the president needs to know and when.

With his periodic treks to the Capitol and his credentials as a former Senate staffer, McDonough has built a deep reserve of good will among lawmakers from both parties. But the botched health care rollout has angered many lawmakers, including Democrats. “This is so important to the president, this is his signature issue,” said Rep. Elijah Cummings, the top Democrat on the Committee on Oversight and Government Reform. “Not only is it his signature issue, it is the signature issue for the Republicans on the negative side. That’s a hell of a combination.”

McDonough is now holding evening meetings every day with key players in the health care rollout. “We went straight into problem solving,” he said last week. “… We knew that we would be confronted with challenges along the way. We are focused on getting it working, absolutely, and we’re making good progress on that.”

‘His personal mission’

Indeed, how the health care website performs on Dec. 1 and beyond will be an acid test of McDonough’s leadership and crisis management. Of all the chiefs of staff who have worked for Obama, McDonough, 43, who rides his bike to work two or three times a week, has the closest relationship with the president. He has been at the center of all recent White House eruptions, from seeking congressional approval for military action against Syria to revelations the National Security Agency had spied on allied leaders.

Still, the debacle has been damaging. Obama’s public approval ratings have sunk. Friends and colleagues say McDonough has taken much of the blow on himself.

“Denis takes everything personally. Nobody is going to be harder on Denis than himself,” said Ben Rhodes, a deputy White House national security adviser. “He was angry, frustrated, all of the above. If there is a problem, it is his personal mission to fix it, even if it is beyond his direct capacity to do so.”