“He can be very acerbic and cutting,” Livingston told the Boston Herald this week.

“His actions directly contributed to the worst economic collapse since the Great Depression,” Livingston added, referring to Frank's approach to the mortgage-finance giants Fannie Mae and Freddie Mac during his tenure atop the Financial Services Committee. “I just think his performance as congressman has been dangerous to the economic health of the country.”

Frank, who retired from Congress this year after 16 terms, churned headlines this week when he announced that he'd like to fill in temporarily for Kerry, should Kerry attain the secretary of State post, ahead of the special election to choose a permanent replacement. Frank has emphasized that he's not interested in the job long-term.

“A month ago, or a few weeks ago, I said I wasn’t interested,” Frank said on MSNBC’s “Morning Joe” program Friday. “It was kind of like you’re about to graduate, and they said: ‘You gotta go to summer school.’"

The recent "fiscal-cliff" deal, however, has inspired a change of heart.

"February, March and April are going to be among the most important months in American financial history," he said. “I’ve told the governor I would now like, frankly, to do that. … Coach, put me in."

Kerry, the chairman of the Senate Foreign Relations Committee, is expected to win his nomination for secretary of State easily, setting the stage for a possible Senate showdown between Rep. Edward MarkeyEd MarkeyOPINION | Shailene Woodley: US should run on renewable energy by 2050 Dems urge 'transparent and inclusive' nuke policy review Senate confirms former Boeing VP as deputy Defense secretary MORE (D-Mass.) and former Sen. Scott Brown (R-Mass.).

Livingston, who served as chairman of the House Appropriations Committee and was Speaker-elect before resigning in 1999 amid a scandal over an extramarital affair, now heads a lobbying firm in Washington.