'Battle-hardened' Summers for Fed head: Altman

It's been said that the head of the Federal Reserve is the second-most-powerful job in the nation. So maybe it's not surprising that the political forces behind each of the emerging lead candidates are pulling out all the stops.

Roger Altman, deputy Treasury Secretary during the Clinton administration, told CNBC on Friday that both Larry Summers and Janet Yellen are infinitely qualified.

Janet Yellen
Kiyoshi Ota | Bloomberg | Getty Images
Janet Yellen

As vice chairwoman, Yellen has been the right hand of Fed Chairman Ben Bernanke, who's not expected to serve a third time when his term ends in January. Summers was Treasury secretary under Clinton and was director of President Barack Obama's National Economic Council.

In a "Squawk Box" interview, Altman said he's looking for "the most battle-hardened veteran" to be the next Fed chairman because the last three decades have seen a "series of big and increasingly frequent financial crises."

"The Fed is the major U.S. firefighter. It's not the Treasury. It's not the Congress. We certainly saw that vividly in 2008," Altman said. "I don't think there's a more battle-hardened veteran anywhere than Larry Summers."

Speculation about Bernanke's future intensified last month after Obama—in an interview with Charlie Rose on PBS—hinted that the Fed chairman may be on his way out.

(Read more: Obama: Bernanke at Fed 'longer than he wanted')

Larry Summers
Jim Davis | Boston Globe | Getty Images
Larry Summers

A possible Summers nomination for the Fed job has faced recent complaints—largely from liberals in the president's own party.

In a closed-door meeting with Democratic lawmakers Wednesday, Obama defended Summers. According to Democrats who were there, Obama also said he's interviewed several possible nominees, but made it clear no decision has been made.

(Read more: Obama mulls Fed pick, defends Summers)

If Obama picks Yellen as the next Fed chair, she'd be the first woman to lead the central bank. It's believed that she would continue on a Bernanke-like path concerning monetary policy.

Summers, on other hand, is viewed as someone who might shake things up a bit at the Fed, which has been engaged in extraordinary measures since the financial crisis of 2008 to help jump-start the economy.

The expected changing-of-the-guard comes as central bank policymakers try to decide when, and if, they should start to taper their $85-billion-a-month bond-buying program. Fed-watchers say a slowdown in purchases could come as soon as September.

—By CNBC's Matthew J. Belvedere. Follow him on Twitter @Matt_SquawkCNBC. Wires contributed to this report.