by FOX NEWS' Jennifer Davis

WASHINGTON, D.C. - President Obama is making many personnel changes as he enters into his 2nd term. Today, the Commander and Chief tapped long time aide Denis McDonough as his new Chief of Staff. McDonough's long been part of the President's inner circle.

"I have been counting on Denis for nearly a decade," says President Obama. "When I first came to D.C., he set up my Senate office."

Most recently, he was a trusted adviser and national security expert, even in the situation room during the Navy Seal raid that killed Usama Bin Laden. Now, McDonough will be the President's 5th Chief of Staff.

"Denis has played a key role in nearly every major national security decision in my Presidency," says President Obama.

McDonough takes over for Jack Lew, now nominated as Treasury Secretary, a position Timothy Geithner stepped down from today. The President announced 9 other senior personnel changes too, part of a wide ranging administrative shuffle.

"We made a number of announcements," says President Obama. "We have a great team."

In a big setback for the President, a Federal Appeals Court has ruled he violated the Constitution by bypassing the Senate with 3 recess appointments to the National Labor Relations Board last year when the Upper Chamber was officially in session, not in recess, a decision that could invalidate hundreds of other board decisions.

"The decision is novel and unprecedented," says White House Press Secretary Jay Carney. "We strongly disagree."

Some transitions may be smoother than others. John Kerry was warmly received at his confirmation hearing Thursday to head the State Department, but things are expected to get more contentious during Chuck Hagel's nomination hearing for Defense Secretary next week.
The President is Making Changes in His Staff