The speech was short on legislative specifics, but the long list of political heavyweights in attendance, including New York State Senator Charles Schumer and other members of New York’s Congressional delegation, seemed to confirm that Mr. Jeffries is a lawmaker whose star is on the rise.

“The fact that all those people showed up is telling,” said Professor Trey Grayson, who leads the Institute of Politics at Harvard’s Kennedy School of Government. “I’ve talked to people in Democratic circles in New York – they’re very high on him.”

Despite Mr. Jeffries’ ambitious political agenda and the wave of goodwill that he rides to Washington D.C., the harsh realities of power and politics in the nation’s capital may hamper the Brooklyn Democrat as he seeks to wield influence in the House of Representatives, according to Congressional experts.

Mr. Jeffries, a 42-year-old New York University School of Law graduate, took his seat representing New York’s Eighth Congressional District on Jan. 3, after easily winning a three-way race to take over for 30-year incumbent Edolphus Towns.

Since then, he has been assigned to the House Budget and Judiciary Committees and has said he’ll use the posts to pursue progressive policy positions, including a push for more gun control. But as a member of the minority party in a sharply divided Congress, it will be very difficult for a freshman lawmaker to have a substantive legislative impact in his first term, political experts said.

“If he’s going to be seen as a rising star, it’s going to be far more symbolic than substantive,” said Jennifer Lawless, a government professor at American University, in Washington, D.C. “Being a freshman in the minority party constricts you in ways that make it virtually impossible to be a leader on any real issues.”

Professor Grayson, a Republican who served two terms as Kentucky’s Secretary of State and lost a Senate primary to Rand Paul in 2010, agreed with Mrs. Lawless that Mr. Jeffries’ chances of getting bills passed or having a substantial effect on policy are slim this early in his career.

But passing legislation is not the only path to recognition, Mr. Grayson said. Becoming the “go-to guy” on a particular issue is one way to gain influence in Congress and developing a robust constituent services operation will keep things copasetic back home in the district, Mr. Grayson said.

Mr. Jeffries’ district is overwhelmingly Democratic and voters there are likely to reliably send him back to Washington, barring something unforeseen. Experts said this is a big advantage for Mr. Jeffries, whose presumed job security will allow him to focus on some of the more mundane details of life in Congress.

“We like political competition in theory,” said David King, a colleague of Grayson’s at the Kennedy School. “In practice, those who face low levels of competition are also those most likely to become policy experts early on.”

There’s an old saying in Washington, that lawmakers are either show horses or workhorses, but Congressional experts said that’s mostly a false dichotomy these days. With the proliferation of media outlets and the never-ending drive for political content, lawmakers may find it much easier to get news coverage in 2013, particularly if they’re willing to express extreme views.

Seniority has always been a powerful part of the culture in Congress and there was a time when new Senators were expected to remain silent for at least a year or two before speaking on the floor. Now, the vise-grip of some of those traditions has eased off a bit, particularly with a bevy of media outlets constantly looking for quotes.

Sen. Ted Cruz, a newly elected Republican from Texas, has quickly made a name for himself in Congress this year, in large part by haranguing Chuck Hagel, who has since been confirmed as the Secretary of Defense. Mr. Grayson also pointed to the relatively quick rise to national prominence of Minnesota Republican Rep. Michelle Bachman (R-MN), an ascendance fueled in large part by cable news appearances.

Congressional experts said Mr. Jeffries, a telegenic lawmaker with a relatively safe seat, has an opportunity to straddle the traditional divide between work and show in Congress, particularly if he can become a fundraising asset for colleagues.

“Be a workhorse when you’re in the chamber, and be a show horse when he’s out on the campaign trail for his colleagues,” Mrs. Lawless said. “I think he’s positioned to be both.”

Mickey Edwards, a political commentator and former Oklahoma Congressman, knows the challenges Mr. Jeffries will face as a freshman in the minority party. Mr. Edwards, a Republican, joined Congress in 1977 and spent each of his eight terms as a member of  the minority party during a long stretch of Democratic control over the House.

“It’s easy to get lost in a place the size of the House, especially with so many ambitious people,” said Mr. Edwards, who has taught government at Harvard and Princeton since leaving Congress. “It’s one of those things where a person who is really committed to making a difference can make a difference, but it requires a lot of energy.”

Mr. Edwards, who operated in a much different media climate 35 years ago, said he choose the path of the Congressional workhorse. He volunteered to help “whip votes” and got on the committee that appoints lawmakers to committees. Over the years, he quietly gained influence and moved up the ranks of his party, retiring as the fourth-ranking Republican in the House.

Mr. Edwards advised Mr. Jeffries to follow his lead.

“The workhorses have influence,” he said. “The show horses are sneered at.”