WASHINGTON » Rick Santorum arrived on Capitol Hill as a new member of Congress in January 1991, 32 years old and bristling with the impatience of a man looking to kick up a fuss. Eight months later, he got his chance when he learned of lawmaker overdrafts at the little-known House bank.

Over beers with rebellious Republican newcomers who became known as the "Gang of Seven," Santorum helped plot a freshmen’s revolt. They would take to the House floor, one by one, to shame Democratic leaders into releasing the check-bouncers’ names.

"We decided to pick a fight," Scott L. Klug, one of the rebels, recalled.

That fight grew into "Rubbergate," a scandal that earned Santorum, who is seeking the Republican nomination for president, a reputation as a reformer and helped land him in the Senate; there, he drew national attention as a pugnacious opponent of abortion and gay rights. Now, heading into a South Carolina primary that he hopes will establish him as the conservative alternative to Mitt Romney, Santorum is spotlighting his time in Congress, branding himself as a "threat to the establishment" who had "shaken things up in Washington" and "wasn’t a member of the club."

But a look at the arc of Santorum’s political career, from his days as fresh-faced College Republican to his bruising defeat for a third term in 2006, reveals a side of Santorum beyond that of reformer and abortion foe. He emerges as a savvy operator and sharp tactician, a climber who became a member of the Washington establishment that he had once railed against.

Santorum won election in 1990 to the House by attacking his Democratic opponent for living in Washington while representing Pennsylvania; by 2006 his critics said the same of him. As the third-ranking Senate Republican, he was a point man in a controversial effort to place Republicans in lobbying jobs. And his finances came into question, amid controversy over political donations and tuition money he accepted.

"There was an evolution there," said G. Terry Madonna, a political scientist at Franklin and Marshall College who has followed Santorum’s career. "He went from someone who criticized the exercise of power and wanted reforms, and turned into Mr. Insider, calling people, making deals."

Santorum spent Thursday basking in the news that he, not Romney, was the top vote-getter in the recent Iowa caucuses. Officials from his campaign did not return calls or emails seeking comment. But John T. Doolittle, a Santorum supporter and member of the Gang of Seven, said Santorum had simply followed the time-worn path of the most effective legislators in Washington from both parties.

"You come as an outsider; some people never really learn the levers of power," Doolittle said. "But others, like Rick, did. You want somebody who can be effective" at using those levers "to advance your values and your ideals."

GOING TO WASHINGTON

On his first day of work in the Capitol, Santorum showed up with a swagger.

The 1990 election cycle had been a tough one for Republicans, and Santorum was among a handful of newcomers who had beaten Democrats. (Another was John A. Boehner, now the House speaker, and a fellow member of the Gang of Seven.) Not only that, Santorum was an unabashed conservative who had won in a swing state. He began by demanding top committee assignments, asserting himself in a way few freshmen would.

"He was part of this group that came in, from the very first moment, and said, ‘We have as much authority in this place as John Dingell or anybody who has been here for 20 years,"’ said Mickey Edwards, a former Republican congressman. "They did not walk in believing we are the new kids and it’s our job to sit back."

Santorum had caught the political bug as a freshman at Penn State in fall 1976, when he volunteered for John Heinz, a moderate Republican running for Senate, to fulfill a class requirement. Soon, Santorum’s course roster was filled with classes on government. He struck professors as ambitious, if more interested in tactics than issues.

"Most students would ask whether a policy would be worth the cost; he was unusual in that he was interested in what would get you the most votes," Robert O’Connor, a former professor, recalled. "I remember him asking me would he be more successful as a Democrat or a Republican."

Santorum’s party affiliation was never really in doubt. He ran the state College Republicans and joined the staff of a Republican state senator. By the late 1980s, as a lobbyist in Harrisburg, he was contemplating running for office. Friends urged him to start out small, but Santorum wanted to go to Washington.

He went after his opponent, a seven-term incumbent named Doug Walgren, accusing him of being too entrenched in the capital. Walgren recalls one particularly effective ad, a cartoon featuring a photograph of the congressman’s home in Washington.

"There was this creepy voice that said, ‘There’s something strange about this house in Washington, D.C.,’ and what was strange was that Congressman Doug Walgren lived there," Walgren said. "He vowed that he would never do that."

LEADING A REBELLION

Not long after coming to Congress, Santorum seized on a cause after seeing a headline in USA Today on Sept. 20, 1991, that read: "Oops — House Members Bounce 4,325 Checks." Santorum and his freshmen friends "were outraged," said Klug, who represented a Wisconsin district at the time. "We had no idea that this bank even existed."

The bank was financed by House members’ paychecks, with overdrafts covered by future deposits, so no tax dollars were involved. For that reason, Norman J. Ornstein, a scholar at the American Enterprise Institute here, said in an interview that he viewed the uproar as "a faux scandal."

But the bank record keeping was flimsy, and the idea of a private House bank played into the notion of cronyism — a perception that Newt Gingrich, then the House Republican whip, was trying to fuel as he plotted a Republican overthrow of the Democratic-controlled House.

Gingrich quietly helped orchestrate the rebellion and gave it what Frank Riggs, another Gang of Seven member, called "tacit support." But Gingrich stayed in the background, knowing the group of newcomers was infuriating senior Republicans, who also enjoyed the benefits of the bank.

Soon the rebels were demanding investigations of other congressional privileges — the House post office, restaurant and barbershop — with Santorum "very much the instigator," Riggs said. Ornstein remembers Santorum as "absolutely relentless."

If the brash young congressman from Pennsylvania irked his fellow Republicans, he did not seem to mind.

"I came down here to shake things up," Santorum told The Morning Call, a newspaper in Allentown, Pa., "and not be shaken."

CHANGE OF FORTUNE

The year 1994 was a good one for Republicans, and for Santorum. His House district had been redrawn to make it more Democratic; fearing he might lose his seat, he gambled and ran for the Senate. He won, beating Harris Wofford, a Democrat appointed to the seat after Heinz died in a plane crash.

There are two ways to rise up the party ranks in the Senate: becoming a committee chairman, which requires seniority and can take decades, or running for a leadership position. In 2000, Santorum was elected chairman of the Senate Republican Conference; Don Nickles, a former senator, remembers him as "too impatient" to wait for a chairmanship.

Instead, Nickles said, "He was a player," with a leadership role that "increases your influence in the Senate."

But there was a downside. Santorum, by this time active in the anti-abortion fight, had carved out a reputation as a rebel. Michael Young, a Pennsylvania pollster, says some Pennsylvanians were surprised to see their senator become "part and parcel of the establishment."

Young believes becoming conference chairman created an internal tension between Santorum’s outsider instincts and his ambition.

"I think ideology met power," Young said, "and it created conflict."

The job required Santorum to coordinate communications strategy for the party, and also to serve as the Republican liaison to K Street, Washington’s lobbying corridor. Santorum held weekly private strategy sessions in the Capitol with top Washington lobbyists; the sessions were intended, participants said, as an exchange of ideas.

"It was a group he trusted, not just run-of-the-mill lobbyists," said Charlie Black, a lobbyist who attended. "He’d tell you what was going on, what they were expecting to do on the floor, and he picked up information from us, because a lot of times people up there lobbying for clients talk to different senators."

The meetings also functioned as a kind of job placement service for Republicans — the Senate version of the "K Street Project," run by Tom DeLay, the hard-nosed House Republican leader. At the sessions, Black said, a Republican National Committee representative would "hand out a list of job openings around town where they might be looking for a Republican." But both he and another lobbyist, Dan Meyer, said Santorum did not pressure firms to hire particular candidates.

"Santorum’s approach was, ‘Let’s make sure we’re identifying openings and working together to identify Republican candidates to consider for these jobs, just as the Democrats do,"’ Meyer said.

The sessions drew negative press — Young said the perception of "cozying up to lobbyists" hurt Santorum as much with Republicans as with Democrats — and he eventually abandoned them. But in 2006, as he was running for re-election, he caught the attention of Citizens for Responsibility and Ethics in Washington, a liberal-leaning watchdog group that had made DeLay its top target.

The group, which goes by the acronym CREW, put Santorum on its list of the "20 Most Corrupt Members of Congress," and accused him of introducing legislation to benefit political donors — an accusation Santorum recently dismissed as politically motivated. "If you haven’t been sued by CREW," he said during a debate in New Hampshire last month, "you’re not a conservative."

As Santorum drew scrutiny in Washington, a political storm was brewing back home, amid revelations that he had accepted $72,000 in tuition reimbursement from the school district in Penn Hills, Pa., where he owns a home. The money was for "cyber-schooling" his children, though they were being home-schooled at the Santorum residence in Leesburg, Va.

Santorum said he was entitled to the money, but the local school district balked, and eventually the commonwealth of Pennsylvania repaid the district a portion of the fees. Questions about his residency were dogging Santorum, as his Democratic opponent, Bob Casey, pushed him on whether he lived in Pennsylvania or in Washington.

"My residence is in Pennsylvania," Santorum insisted during one televised debate. "That’s where I pay my taxes. That’s where my driver’s license is."

For Santorum, already weighed down by his ties to an unpopular president, George W. Bush, the tuition dispute made a bad political year worse. He lost to Casey by 18 points.

Those with memories of his early campaigns took some satisfaction in his crushing defeat, saying things appeared to have come full circle for the man who once said he wanted to shake up Washington. Among them was Erin Vecchio, a Democrat and then a Penn Hills school board member, who stirred up the residency debate.

"I remember him going after Doug Walgren," Vecchio said, "and it just really irked me."