The son of a New Jersey truck stop operator, Frank is a graduate of Harvard College and Harvard Law. Between the upbringing in Jersey and the ivory towers of Cambridge, Frank developed a smarter-than-thou attitude and a liberal outlook that led to a life in politics. He served as a member of the Massachusetts House and then was elected to the US House from his Newton district in 1980.

Representative Peter King, a conservative New York Republican who serves on the House Financial Services Committee with Frank, said “some Republicans are going to say good riddance.’’ But others, King said, “will say he was always a very worthy adversary. And he made you earn your money. If you’re going to get up on the House floor and debate Barney, you better know what you’re talking about.’’

“He’s a force of nature and he cannot be replaced, irrespective of party,’’ said William Delahunt, a former representative who has known Frank since they served together in the Massachusetts Legislature in 1973. “He will be hugely missed,’’ said Senator John Kerry, the Massachusetts Democrat.

That made him a prominent enemy of conservatives, who used Frank as a foil to rally their troops and raise money to defeat Democrats.

And, unlike so many other politicians in a city that relies on message control, he has done it not by press release or through a spokesman or even through Twitter. Instead, with his patented put-down, his trademark sardonic analysis, or just plain bluster, the man often referred to as “the mouth that roared’’ could be counted on by television hosts to fire away on behalf of the liberal agenda.

He also fought aggressively for gay rights and championed repeal of the ban on homosexuals openly serving in the military.

His impact on debate and policy has been among the most significant of any recent House member outside the speaker’s office. In his powerful position as House Financial Services Committee chairman, Frank was a crucial backer of the bank bailout of 2008, and, with former senator Christopher Dodd of Connecticut, engineered the overhaul of Wall Street regulations, a measure designed to reduce the likelihood of another meltdown.

Love him or hate him, call him brilliant or - like O’Reilly and other conservatives - accuse him of precipitating the nation’s financial meltdown with his advocacy for more lenient mortgage lending standards, Frank has for his 31 years in Washington been impossible to ignore.

“You don’t listen at all, or maybe you are listening or you’re too dumb to understand,’’ Frank, the liberal icon, lectured to Fox News’s conservative talk show host, Bill O’Reilly.

WASHINGTON - It was a classic Barney Frank moment, filled with anger, pride, bluster, outrage, and confrontation. And it was on live television.

In 1987, Frank said for the first time publicly, in an interview with the Globe, that he was gay and pronounced it irrelevant to his job. “So what?’’ he said.

Eventually, however, Frank’s private life became very public. He had previously hired a male prostitute and used personal funds to pay him as an aide. When it was reported in 1989 that the man had run a prostitution ring from Frank’s Washington home years earlier, the lawmaker’s actions came under investigation.

Frank had denied he knew the man was running a prostitution ring. The House eventually voted 408-18 to reprimand Frank for using his congressional office to fix 33 of the man’s parking tickets. Frank was reelected in 1990 with 66 percent of the vote.

He had survived being written off by some as politically dead and rejected the advice of an editorial by the Globe calling for his resignation.

Despite the scandal, Frank did not step back from advocating for gay rights.

“He really showed that this was something that was possible, that you could make a difference and be yourself,’’ said Christine Quinn, the first openly gay City Council speaker in New York City who has cited Frank’s career as an inspiration. “He’s really a hero to all of us.’’

Frank became more outspoken than ever. Perhaps his most famous one-liner was his rebuke of conservative opponents of abortion rights. He said their concern for life “begins with conception and ends with birth.’’

Although hailed by supporters and pilloried by foes for his liberal stances, Frank was known for his ability to work with Republicans on certain issues. In fact, Frank found an unlikely ally in Senator Scott Brown, the Massachusetts Republican who convinced him to add a provision in the Dodd-Frank bill that would exempt some insurance and mutual fund companies from certain regulations. Brown then cast a critical vote needed to break the GOP filibuster against the bill.

The Dodd-Frank law was in response to the credit meltdown of 2008, a financial calamity caused largely by problems in the housing market that were greatly amplified by the financial industry’s buying and selling of bundles of loans. For years, Frank had worked enthusiastically to help lower-income people get home mortgages with the help of the quasi-government agencies, Fannie Mae and Freddie Mac.

As early as 2003, Frank and other members of the Financial Services Committee had received reports from the director of the federal office responsible for overseeing Fannie and Freddie questioning their solvency, given their expanding portfolios and increasing reliance on risky investments.

But Frank continued to defend the lenders. He did not take action to rein them in until he became chair of the committee in January 2007. By the time he passed a bill out of committee requiring tighter restrictions on Fannie and Freddie, it was too late - the lenders had gobbled up risky mortgages and were headed for failure amid the foreclosure crisis.

Last fall, in an interview with the Globe, Frank acknowledged that he had seen the problems with Fannie and Freddie too late. He said he had been wearing ideological blinders; he had worried that Republicans were going after Fannie and Freddie for their own ideological reasons and would curtail the lenders’ mission of providing affordable housing.

“I was late in seeing it, no question,’’ Frank said about the lenders’ descent into insolvency. It was this episode that caused conservatives, including Fox’s O’Reilly, to castigate Frank. Frank responded that Republicans controlled Congress for much of the time and shared the blame.

Then, in a presidential debate this year, Frank’s longtime nemesis, the former speaker of the House, Newt Gingrich, said Frank should be jailed for his role in the housing mess. When it was later reported that Gingrich had taken at least $1.6 million in fees from Freddie Mac, Frank took to the airwaves and assailed Gingrich as “a man with no ethical core whatsoever.’’

Whether in his final days in Congress or in retirement, a friend said, Frank will continue to defend his financial industry regulations against repeal attempts from the GOP.

Michael Kranish can be reached at kranish@globe.com. Tracy Jan can be reached at tjan@globe.com. Donovan Slack of the Globe Washington Bureau contributed to this report.

© Copyright 2011 Globe Newspaper Company.