President Obama said Thursday he picked Jack Lew to be Treasury secretary because his vast experience and even temperament will help him negotiate budget battles with Congress and continue rebuilding the economy.
"A lot of work remains, especially to build a strong middle class," Obama said in unveiling the Lew nomination during a brief White House ceremony.
Lew, the current White House chief of staff and former budget director for Obama, said in a brief statement he looks forward to "the challenges ahead."
Obama chose Lew to replace Timothy Geithner, whom the president said would go down in history as "one of our finest secretaries of the Treasury."
Geithner returned the praise, saying Obama inherited "the worst crisis in generations" when he took office in 2009, and "saved the global economy."
In praising Lew, Obama noted that he helped forge a new Social Security plan in 1983 while an aide to House Speaker Tip O'Neill, D-Mass., and he produced a balanced budget while budget director for President Clinton in the late 1990s.
The White House ceremony also featured jokes about Lew's remarkably poor penmanship -- something of an issue because the Treasury secretary's signature appears on all U.S. currency.
Obama said Lew promised to improve his legibility "in order not to debase our currency."
The Treasury secretary and the rest of Obama's economic team face three big budget battles in the next three months with congressional Republicans:
• The parties are still trying to negotiate a debt-reduction deal to head off a series of automatic budget cuts set to take effect in March. The so-called sequester -- including popular defense and domestic programs -- was delayed two months as part of the "fiscal cliff" agreement on New Year's Day. That agreement dealt with taxes.
• The government's authority to borrow money to pay its bills - the "debt ceiling" - is expected to expire in two months or so. Some Republicans said they won't support an increase in the debt ceiling without corresponding budget cuts.
• The continuing resolution to fund the government expires May 27. The parties must negotiate an extension or face the prospect of another government shutdown.
While Lew is considered a good bet for confirmation, Alabama Sen. Jeff Sessions, the top Republican on the Senate Budget Committee, said he would try to block the nomination. Sessions cited Lew's congressional testimony in 2011 that Obama's plans would not add to a federal debt that now tops $16 trillion.
"His testimony before the Senate Budget Committee less than two years ago was so outrageous and false that it alone disqualifies," Sessions said.
Utah Sen. Orrin Hatch, the ranking Republican on the Senate Finance Committee, said he wants Lew to "outline the administration's plans on tackling our unsustainable debt, what areas of federal spending should be cut, and what kind of reforms -- from our tax code to our entitlement programs -- are needed to get our fiscal house in order."
The Lew nomination is the latest move in a Cabinet shuffle that precedes the start of Obama's second term on Jan. 20.
Others who are departing the Obama administration: Secretary of State Hillary Rodham Clinton, Defense Secretary Leon Panetta, Labor Secretary Hilda Solis and Environmental Protection Agency Administrator Lisa Jackson.
Obama has nominated Sen. John Kerry, D-Mass., to replace Clinton at State, and former senator Chuck Hagel, R-Neb., to replace Panetta at the Pentagon. The president has also tapped counterterrorism aide John Brennan for CIA director to replace David Petraeus, who resigned in November over an extramarital affair.
Attorney General Eric Holder, Health and Human Services Secretary Kathleen Sebelius and Veterans Affairs Secretary Eric Shinseki will remain at their posts, officials said.
Obama has not yet made new selections for the Labor Department and the EPA.
And, with the promotion of Lew, he will need a new chief of staff as well.