But during her first extensive interview since her victory last month, Warren said she had no bills or initiatives ready to propose when she becomes senator next month. Instead, she said, she is studying the ways of the Senate, looking into issues that others have proposed, and seeking out alliances.

The conciliatory approach may surprise those who expected the self-proclaimed rock-thrower to arrive with a slingshot, and play the role of constant critic, forever dishing with Jon Stewart and Rachel Maddow.

Warren, who once promised to throw her body in front of bad bills if she won office, acknowledged that in the Senate, with its tradition of deference to senior members, the road to power often requires discretion.

“Here’s how I see this,” Warren said. “My job is to be effective on behalf of Massachusetts, and so what I’m trying to parse through is the difference between how much of this is about your own initiative, how much it’s about finding other bills that are really what you’d like to see get done and offering to be helpful, [and] how much it’s looking for the little cracks that are windows of opportunity.”

Certainly, Warren is not promising a retreat. She said she will continue to be an outspoken voice on her priorities, which she described as filibuster reform, lowering college debt, financial regulation, and public infrastructure and clean energy investment, all of which she said will help the middle class. She said she wants to repeal the Defense of Marriage Act, which the Supreme Court also announced on Friday that it would review.

“I’m not patient,” she said, as if to assure supporters she won’t be tamed. “I’m not patient.”

But she said she will choose her tactics carefully, keeping quiet when it suits her objective and making noise when she sees the need.

“I don’t think those are inconsistent,” she said. “I want to use every tool in the tool box because I want to help get things done. And sometimes the best way to do that is quietly, let everyone else take credit and, sometimes, it’s to be willing to stand outside and call everyone out over it. I’m open to any part of that.”

She described her crowning policy achievement, the creation of the Consumer Financial Protection Bureau that raised her national profile, as one of those cracks of opportunity, a once far-fetched notion that became possible after the bank bailouts infuriated much of the nation.

“I knew they were going to have to rewrite the financial rules,” she said. “And if they’re going to have to rewrite the financial rules, that’s going to create an opening to rethink consumer finance.”

During an hourlong interview in the office of her campaign adviser, Doug Rubin, Warren looked as if she had regained much of the energy that had been sapped in the aftermath of a yearlong campaign. She tapped her fingers on the table to underscore points, went off on spirited tangents about the need for medical research spending, and joked that she is losing job security by giving up lifetime tenure for a mere six-year term in the Senate.

Warren’s victory on Nov. 6 elated Democrats around the country, and vanquished Brown, a rising star in the Republican Party. Their contentious battle was the nation’s most expensive Senate race, with about $80 million spent between the candidates. Early in the race, Warren introduced herself to the Democratic base as an uncompromising fighter for the middle class and a liberal counterweight to the Tea Party.

In her interview last week, Warren showed a caution that has developed over the last year, as she evolved from a watchdog working outside the power structure into a political player entering its inner sanctum.

On one of the most pressing issues knotting Washington, the fiscal cliff, Warren avoided drawing bright lines. She declined to describe specific tax rates and spending cuts she would endorse as part of a deal to avert the mandatory tax hikes and spending cuts that will take effect at month’s end unless Washington reaches a deal.

“I don’t know how to answer the question,” she said. “Let’s see what they’ve got.”

Warren will be sworn in Jan. 3, when it’s possible a deal could already be in place.