After passing immigration reform, a farm bill, and this week's student-loan legislation, there's an air of accomplishment in the Senate. And for one freshman senator, it smells like opportunity.

Angus King, an independent from Maine, notched his first high-profile victory this week since joining the chamber in January. King, along with a bipartisan group of lawmakers, crafted an agreement to lower student-loan interest rates, which cleared the Senate on an 81-18 vote and appears headed for passage in the House.

For King, 69, who quotes Mick Jagger and refers to himself as the "world's oldest freshman," the agreement sends a signal to colleagues that he can help broker deals. But it also provides him with the political capital he'll need if he wants to move up in the Senate, where political power follows a traditional path.

"The typical way you gain influence and power in the Senate is through seniority," King said in an interview. "I'm not gonna be here 30 years. So I have to try to achieve influence in different ways."

Independent senators also face unique barriers to rising on committees, which are controlled by the majority party. They historically ascend to chairmanships because of their previous status within a party or because a deal was cast around their party change.

Of the 10 senators since World War II who have identified as independent or third-party, only two (excluding Strom Thurmond, who eventually became a Republican) went on to chair committees, according to data from the Senate historian. Jim Jeffords of Vermont went from Republican to independent and, in return for caucusing with Democrats, was granted the chairmanship of what is now the Health, Education, Labor, and Pensions Committee. Joe Lieberman of Connecticut lost a Democratic primary in 2006 but won in the general election and went on to chair the Homeland Security Committee, caucusing with Democrats.

King, who does not fit the mold of either man, has given thought to how he might move up in the chamber, and says he realizes that he's not likely to chair a committee (though possibly a subcommittee). But he sketches another path to power using a nontraditional playbook.

"It's really trying to earn the respect of my colleagues and gain influence that way," he said.

And collaborating on high-profile deals like the one made over student loans raises a lawmaker's visibility. To reach an agreement, King found himself working with Republican Sens. Lamar Alexander of Tennessee, Richard Burr of North Carolina, and Tom Coburn of Oklahoma, as well as Democrats Thomas Carper of Delaware, Dick Durbin of Illinois, Tom Harkin of Iowa, and Joe Manchin of West Virginia.

"It's nice to get thrown into a big bill all at once," said fellow freshman Sen. Jeff Flake, R-Ariz., who was part of the "Gang of Eight" that helped move immigration reform. "I got to know a lot of members of the body I wouldn't know so quickly."

King looked at the student-loan-rate issue in part through that lens, but decided to engage on the issue after he observed failed votes on modifying the sequester earlier this year. Republican and Democratic proposals couldn't reach 60 votes, and that's when King says the "central reality of Washington" became clear to him.

"It's just arithmetic," he said. "If you need 60 votes and there are 52 Democrats and 2 independents, you gotta have some number of Republicans or nothing's gonna happen."

Earlier this year, two Democratic votes on extending a lower rate on subsidized Stafford loans, which doubled from 3.4 percent to 6.8 percent on July 1, failed. That, as King tells it, set the bipartisan group in motion.

About six weeks ago, King and Manchin began discussing a measure they thought could clear Congress and make it to the president's desk. The common thread was that they were former governors.

"Angus, he approached me," Carper said. "He and Joe Manchin, Lamar Alexander, all of us recovering governors, and basically said this is something we governors can help solve."

Lawmakers hashed the deal out over many meetings and King said the tone throughout was collegial, both among lawmakers and staff. Early on in the negotiations, it was clear that tying rates to a market indicator would be important for securing Republican support. The group settled on the 10-year Treasury note and lawmakers agreed the deal should be as close to deficit neutral as possible.

The final item of negotiation—and a sticking point among some Senate Democrats—was caps on interest rates. During an hour-long meeting at the White House—King's first trip there—the group and President Obama persuaded Harkin, who chairs the HELP Committee, to accept the proposal.

"The key was Harkin's support," King said. Even after Harkin signed off on the deal, King says he never felt certain it would pass for sure. And with good reason. Senate liberals opposed the proposal, and offered two amendments, including one aimed at sunsetting the provisions of the deal. But they failed to get 60 votes. Still, Durbin and Majority Leader Harry Reid voted for one of the amendments, in a sign of just how much liberals thought they were giving up.

The Senate-passed measure provides that federal student-loan interest rates would equal the 10-year Treasury note at the time the loan was taken out, with an additional percentage on top: 2.05 percent will be added to undergraduate rates, with an 8.25 percent cap, and 3.6 percent will be added to graduate loans, with a 9.5 percent cap. For PLUS loans, 4.6 percent would be added, with a 10.5 percent cap.

After the bill cleared the Senate, Maine's senior senator, Republican Susan Collins, extended her hand to a smiling King and told him, "good job."

A member of the Budget Committee, King said he plans next on trying to help break the partisan gridlock over spending and the debt limit. It's no small task, but King's Democratic colleagues are bullish on his involvement moving forward.

"Angus is a big part of the glue that [held] the deal together and he helped convene everybody," Carper said. "I think it could be a prelude to a lot more of the same."