She stands less than 5 feet tall and counts humor as her secret weapon. Today, she makes history.
Sen. Barbara Mikulski, a 74-year old Maryland Democrat, likes to say how unlikely it is that someone like her would ever come to the U.S. Senate. But today, as the 112th Congress convenes, she becomes the longest-serving female senator in U.S. history.
"I never thought of myself as a historical figure. But when the Library of Congress called and said, 'You're going to break the Margaret Chase Smith record, and we want historical artifacts,' I was taken aback," Mikulski told ABC News' Diane Sawyer. "To me, history is powder wigs and Jane Addams and Abigail Adams. Both pioneers in their own right.
"I think, for me, it's not how long I've served, it's how well I've served."
Tune in to 'World News With Diane Sawyer' Friday at 6:30 p.m. ET to watch Barbara Mikulski honored as our 'Person of the Week'
And with the new Congress, coming off contentious midterm elections that saw her party get thrashed at the polls, Mikulski said Republicans and Democrats need to work at civility.
"I think it's going to be full of challenges. We're going to want to stop bad things from happening," she said.
"We'll fight the repeal of Obama health care. We don't want to privatize Social Security," she said. "But we've got to work for a strong economy. And this is why I'd like to get back to that strong feeling of bipartisanship."
Mikulski said she already "kind of surveyed the women" after the election to get to know them and to build a consensus on certain issues.
"Even where we disagree, we don't have to be disagreeable. We're not a caucus. We disagree on issues like pro-choice, where to cut the budget," she said. "But we are a force," often on such issues as women's health care.
Mikulski, the daughter of a Baltimore grocer, said that when she was growing up, politics was a world away.
"Old guys who smoked cigars with potbellies, and they were named Tom, Dick and Harry," she said. "Now politicians are named Barb, Bev and Hillary."
But Mikulski secured a seat on the Baltimore City Council in the early 1970s, followed by a seat in the U.S. House of Representatives a few years later.
She described her best day in Congress as the day she stood on the Senate floor and fought for preventive health care for women, an amendment that later passed.
Her worst day, she said, was Sept. 11, 2001, when she and the rest of Congress were forced to run from what they feared would be an attack on the Capitol building.
"I'm a little on the chunky side, but I tell you I ran all the way and over to the Supreme Court and didn't break a sweat," she said. "It was a terrible day.
"But that day when we stood on the Capitol steps and bipartisans sang 'God Bless America,' I would never want to go back to that day. But I would like to go back to that feeling of togetherness."
Although Mikulski makes history today, for her it's just another marker in a long line of firsts.
She was the first Democratic woman elected to the Senate, the first Democratic woman to serve in both houses of Congress, the first Democratic woman senator elected to a leadership post, the first woman elected to statewide office in Maryland -- and the list goes on.
Lest anyone think that Mikulski's tenure on Capitol Hill has been only about milestones, it has also been one of historic legislative accomplishments.