US President Barack Obama's former chief of staff Jack Lew was confirmed Wednesday as the next US Treasury secretary, taking over a key portfolio at a time of deadlock over the budget and debt.

The US Senate voted 71-26 -- with support from 20 Republicans -- to confirm Lew, a former White House budget director and Wall Street executive, providing Obama with a second new cabinet appointment approval in as many days.

A day earlier, the chamber voted to confirm Chuck Hagel to head the Pentagon, after a contentious, seven-week process.

While Hagel's confirmation was marked by partisan acrimony and delays, Lew's nomination sailed through, and the president issued a swift thanks to the Senate for its bipartisan action.

"At this critical time for our economy and our country, there is no one more qualified for this position than Jack," Obama said in a statement.

"As my chief of staff, Jack was by my side as we confronted our nation's toughest challenges," the president said, hailing Lew as "a master of fiscal issues who can work with leaders on both sides of the aisle."

"I will continue to rely on his advice and sound judgment as we work to create good, middle-class jobs."

Lew, expected to be sworn in early Thursday, replaces Timothy Geithner, who steered the Obama administration through the financial crisis.

The White House is now locked in a new showdown, this time with Republican lawmakers over how to avoid some $85 billion in across-the-board spending cuts that are set to kick in from Friday.

Lawmakers acknowledge the deadline will likely pass without a deal to avert the cuts, and that those negotiations would be rolled into next month's debate over 2013 government funding levels.

Lew, who was a prime budget negotiator in 2011, is likely to be involved in the March negotiations.

His nomination was not without hiccups. Some Republicans, notably Senator Jeff Sessions, highlighted Lew's reputation as a dogged defender of Democratic party stances in budget negotiations with White House opponents.

Sessions cited Lew's statement in early 2011, when he said the proposed budget would add nothing to the national debt.

But Sessions said on the Senate floor that the budget would have enlarged the debt by some $600 billion per year over the next decade, and he blasted Lew's statement as the "greatest financial misrepresentation in (US) history."

One senator who caucuses with the Democrats, independent Bernie Sanders, voted against Lew, while some Democrats revealed their discomfort in having a Wall Street insider in the position.

First-term Senator Elizabeth Warren, who made her reputation defending Americans from Wall Street abuse, said she was "very hopeful" Lew would be a good Treasury chief.

But the Obama administration "still has work to do to fix the housing market and reduce the risk of future crises," she added.

"I do not believe that putting Wall Street executives in key assistant secretary and regulatory positions is a cure-all for our problems."

Lew, 57, worked under president Bill Clinton in the Office of Management and Budget after an earlier start as a congressional aide and as an attorney in the private sector.

In 2001, he moved to New York University, and then in 2006 was recruited by Citigroup, where for two years he was chief operating officer in the alternative investments unit.

The huge payout Lew received when he left the bank to join the Obama administration, a bonus stipulated by his contract, sparked concern that he is too close to the banks and would be too accepting of the practices that stoked the financial crisis.

Lew is seen as an accessible and attentive listener but rarely strays from his serious demeanor -- although he has a loopy side that is about to get much more visible.

As Treasury secretary, Lew's signature will appear on all new US bills printed, and his autograph has the look of a cute but undecipherable first grader's doodle.

The president has a handful of other posts to fill, including replacements for secretaries of transportation, energy, labor and interior.

And he faces tough going for John Brennan, his pick to head the Central Intelligence Agency.

Some Republicans have threatened to block Brennan's confirmation over the lack of White House information on the secret drone program or the attack on a US outpost in Benghazi, Libya last September 11 that killed four Americans.

Dianne Feinstein, who chairs the Senate Intelligence Committee, said a committee vote on Brennan's nomination will be scheduled for March 5