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President Barack Obama announces his choice of White House Chief of Staff Jack Lew as the next Treasury Secretary in the East Room of the White House on January 10, 2013 in Washington, DC.

President Barack Obama nominated Jack Lew, his current chief of staff, to be the next Secretary of the Treasury Thursday, elevating his wonky former budget director to a position at the center of fights over the nation's deficit and spending. 

"Jack knows that every number on a page, every dollar we budget, every decision we make, has to be an expression of who we wish to be as a nation, our values," the president said at the White House announcement of Lew's nomination.

Related: Team Obama trips on cabinet shuffle

The president did not indicate who will replace Lew. The leading candidates for the next chief of staff are former Biden chief of staff Ron Klain and Deputy National Security Adviser Denis McDonough. 

"I don't want to see him go, because it's working out really well for me to have him in the White House," Obama said of his departing chief. "But my loss will be the nation's gain."

Lew, known as a tough negotiator who clashed with House Republican aides during last year's debt ceiling negotiations, previously served as the director of the Office of Management and Budget under both Obama and former President Bill Clinton. 

Lew will replace outgoing secretary Tim Geithner, who took the post at the start of Obama's first term, when financial markets were still roiling from the 2008 meltdown. 

"I couldn't blame Tim when he told me he wasn't the right guy for the job," Obama joked. 

Praising Geithner for his handling of the economy throughout his four year tenure, Obama noted that he pleaded with Geithner to stay on despite his onetime desire to leave before the end of Obama's first term. 

"When the history books are written, Tim Geithner's going to go down as one of our finest Secretaries of the Treasury," Obama said to sustained applause from the audience at the White House. 

In remarks, Lew joked about his famously loopy signature, saying that he and Geithner share "a common challenge with penmanship." (The Treasury Secretary's signature appears on all paper currency.) 

Obama wryly responded that, while he considered rescinding Lew's nomination over his sloppy signature, the new pick had promised to work to make at least one letter legible so as to "not debase our currency." 

Critics have pointed out that Lew, who served as chief operating officer of Citigroup Alternative Investments in 2008 before coming to OMB, benefited from that unit's investments in anticipation of the housing market collapse.

That's likely to be discussed at his confirmation hearings, and Republicans like Senate Budget Committee ranking member Sen. Jeff Sessions have already voiced opposition to Lew's selection for the post. 

On Thursday, Chamber of Commerce President Tom Donohue described the new Treasury pick as an experienced veteran of fiscal debates. 

"Jack's been around for a long time," he said. "He's a tough dude." 

For more about Lew's background, click here to read NBC's coverage from yesterday. 

NBC's Bob Costantini contributed to this report. 

Chip Somodevilla / Getty Images file

President Obama is expected nominate Jack Lew, left, as the Treasury Secretary, replacing Timothy Geithner, right, pictured here during a press conference Sept. 19, 2011 in Washington, D.C.

Updated 12:15 p.m. ET -- President Barack Obama will announce current White House Chief of Staff Jack Lew as his pick to be the next Secretary of the Treasury, CNBC's John Harwood confirmed Wednesday. The announcement could come as early as Thursday.

Lew, who previously served as budget director under Obama and President Bill Clinton, has long been considered the frontrunner to replace departing Secretary Timothy Geithner, the last remaining member of Obama's first-term economic team.

A former investment banker and Capitol Hill aide, Lew was instrumental in crafting the August 2011 debt deal that created the automatic tax increases and spending cuts narrowly avoided in the New Year's "fiscal cliff" agreement.

Those negotiations didn't make Lew a hero to congressional Republicans, who were reportedly irked by his style. Journalist Bob Woodward wrote in his book "The Price of Politics" that top aides to House Speaker John Boehner found Lew "disrespectful and dismissive" and "obnoxious" during the talks.

But, despite the bruising fight set up by the cliff built in the August talks, Lew's strategy ultimately helped set up what observers have deemed a political victory for Obama early in 2013.

A 57-year-old native of New York City, Lew's long familiarity with Capitol Hill began when he took a job as a legislative aide in 1973. He went on to serve for nine years as chief domestic policy adviser to House Speaker Tip O'Neill.

While Lew's announcement is expected soon, per CNBC's Harwood, it's not clear that the president has settled on his new choice for chief of staff.

Deputy National Security Adviser Denis McDonough and former Biden chief of staff Ron Klain are both seen as potential Lew replacements.

Related content:

Jack Lew's loopy signature may have to go

With the congressional storm over debt and spending temporarily calmed after the fiscal cliff fight, the political world's attention now turns to the administration's shuffling of top agency jobs at the start of President Barack Obama's second term.

The president's cabinet includes 15 heads of federal departments, appointed by the president and confirmed by the Senate. As Obama’s first term comes to an end, there remains plenty of uncertainty about as to the status of much of the cabinet, including some of the top positions in the government.  Here’s what we know so far: 

Secretary of State: Obama has already announced Sen. John Kerry as his pick to succeed departing Secretary of State Hillary Clinton, choosing the Foreign Relations Committee head after his other reported top choice, Susan Rice, withdrew from consideration for the post. Kerry is expected to be confirmed easily by his Senate colleagues.

Kevin Lamarque / Reuters

President Barack Obama announces the nomination of Sen. John Kerry as Secretary of State to succeed Hillary Clinton, at the White House in Washington Dec. 21, 2012.

Secretary of Defense: An administration official has confirmed to NBC's Chuck Todd that President Obama plans to nominate former Sen. Chuck Hagel, a Nebraska Republican and Vietnam veteran, for the Defense secretary position on Monday. Hagel would replace Leon Panetta at the helm of Defense Department.

The Nebraska lawmaker faces significant opposition from some in his own party who are wary of Hagel's past statements about Israel. Hagel was also forced to issue an apology after foes resurfaced a 1998 comment in which Hagel criticized an "aggressively gay" political appointee.

In an interview with NBC’s “Meet the Press” last week, Obama praised Hagel but said he has not made a final decision about who he wants for the top Pentagon job. 

"I haven't made a decision about who to nominate," Obama said. "And my number one criteria will be who's going to do the best job in helping to secure America."

If nominated, Hagel would be boosted by two heavyweights other than the president: Vice President Joe Biden and Rhode Island Sen. Jack Reed. 

Other possibilities reportedly discussed for the post were Former Undersecretary of Defense for Policy Michele Flournoy, or Deputy Defense Secretary Ashton Carter.

Treasury Secretary: Current Treasury Secretary Tim Geithner, the final remaining member of Obama's original economic team, has signaled that he will step down after the inauguration, which could leave the department without a confirmed chief during the coming showdown over the debt ceiling. White House Chief of Staff Jack Lew, a former director of the Office of Management and Budget, is considered to be Geithner's likely successor.

But as NBC's Political Unit notes, the White House may think twice about handling a confirmation process at the same time as yet another round of brinkmanship over the government's legal borrowing power.

Jason Reed / Reuters

President Barack Obama walks off stage with Treasury Secretary Tim Geithner after speaking about his meeting on infrastructure investment, in the Rose Garden of the White House in this Oct. 11, 2010 file photo.

CIA Director: While not technically a Cabinet position, also in the mix will be a new intelligence guru to replace former CIA Director Gen. David Petraeus, who resigned after admitting to an extramarital affair with his biographer.

In the running for that job are John Brennan, an influential White House adviser on counter-terrorism, as well as acting CIA Director Michael Morrell.

Other Cabinet positions:  Along with the candidates for those high-ranking positions, there will likely be other openings throughout the administration, with possible departures from other agencies including the Energy and Commerce departments.

If Interior Department head Ken Salazar chooses to leave, former Sen. Byron Dorgan of North Dakota, retiring Rep. Norm Dicks of Washington, and outgoing Washington Gov. Christine Gregoire are on the shortlist to replace him,  according to a Democratic insider.

Environmental Protection Agency head Lisa Jackson has also announced her departure at the end of January, setting up an open position at an organization frequently targeted by Republican foes of federal regulations. (The EPA chief job is not among the 15 official Cabinet positions but is awarded the status of "cabinet rank.")

Earlier today, Bloomberg News reported that Treasury Secretary Tim Geithner is planning to leave the Obama administration by the end of January, even if the White House and Congress haven't yet reached a deal on the debt ceiling by then.

In response to a question from First Read about the article, a Treasury spokesperson says that Geithner has previously stated he plans to stay "until around the inauguration" -- so late January.

"Secretary Geithner has previously stated that he plans to be at Treasury until around the inauguration," the spokesperson said. "We do not plan to make any further announcements about the timing of the Secretary's departure until after his successor is named."

Geithner, 51, is the only remaining original member of Obama's cabinet and has been an instrumental figure in the administration's handling of the bank bailouts and economic recovery efforts in the wake of the 2008 financial crisis. 

Prior to joining the Obama administration, Geithner served as the president and CEO of the Federal Reserve Bank of New York. He first joined the Treasury department in 1988 and served in various roles under three separate administrations.  

One possible contender for the job after Geithner's departure is current White House Chief of Staff Jack Lew, who previously served as the Director of the Office of Management and Budget.

NBC's Carrie Dann contributed to this report.  

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