Allison Silberberg, the newly elected mayor of Alexandria, poses for a portrait in Old Town. (Nikki Kahn/The Washington Post)

The mayor-elect of Alexandria was struggling to make a motion.

“It sounds like we have to detail it right down to the nub?” Vice Mayor Allison Silberberg (D) asked no one in particular after several attempts to propose a delay in waterfront development during a December City Council meeting. “I welcome to hear from my, our, colleagues.”

There was a long silence. Eventually, Mayor William D. Euille (D) called a 10-minute recess. When the meeting reconvened, Silberberg offered the motion but could not get a second. She was alone in her position, as she has been many times in the past three years.

The 52-year-old writer and community volunteer who on Monday will be sworn in as mayor presents a stark contrast in both style and substance with Euille, a four-term incumbent whom she defeated in the June primary and again in November, after Euille launched a write-in campaign.

Mayor-elect Allison Silberberg attends the 45th annual Scottish Christmas Walk Parade. (Michael S. Williamson/The Washington Post)

He is extroverted; she is reticent. He believes the waterfront needs more housing, hotels and retail; she wants to slow the pace of development. And while Euille is a master negotiator and lawmaker, Silberberg is still learning the legislative ropes.

“It’s a whole different style, for sure,” said council member Redella S. “Del” Pepper (D), a city lawmaker since 1985. “This will be her opportunity to set her own pace and agenda.”

Political from an early age

One of three daughters of a father who was a petroleum engineer and a mother who ran former Texas governor Ann Richards’s North Dallas campaign office, Silberberg counts as a mentor Adlene Harrison, 92, who spent three months as mayor of Dallas in 1976 — the first woman and the first Jewish person to hold that position.

Even as a child, Harrison said in an interview, Silberberg listened closely and asked a lot of questions. “She believes what she believes, and she isn’t going to change,” Harrison said.

An avid amateur athlete, Silberberg says she was not yet 6 years old when she was taught how to throw a football by Calvin G. Hill, the former Dallas Cowboys running back who was a friend of a friend. “I have a really good throwing arm,” she said, recalling that she used to carry a football in her car in search of a pick-up game.

Asked whether she considered herself a jock, she ducked away from that label, saying: “I have a lot of enthusiasm. I do like sports. I like the camaraderie and I like trying to improve.”

She came to Washington to study history and international relations at American University. After graduating in 1984, she interned for Sen. Edward M. Kennedy (D-Mass.), later working for Sen. Lloyd M. Bentsen (D-Tex.). She received a master’s degree in playwriting at UCLA in 1987 then moved to Alexandria in 1989.

In the 1990s, she started “Lights, Camera, Action,” a nonprofit filmmaking program for youth in Anacostia. In the early 2000s, she was appointed to Alexandria’s Economic Opportunities Commission, which advocates for low-income residents, eventually becoming its chair.

“She has a way to make her ideas your ideas,” said Eileen Cassidy Rivera, a friend since college. “She really knows how to . . . listen to the pulse of the community.”

Silberberg recently co-wrote a book for the Society for Women’s Health Research and has published two others: “And Life Will Be a Beautiful Dream,” a commissioned work about a philanthropic family, and “Visionaries in Our Midst,” a collection of essays that profiles people who have created or led nonprofit agencies.

It was a 2011 opinion piece published in The Washington Post opposing Alexandria’s waterfront development plan that served as the platform for her first run for office.

As the top vote-getter among council candidates in 2012, she became vice mayor. Three years later, convinced that Alexandria was still rushing to develop too much of the city too quickly, she decided to go for the top job.

Challenges physical and fiscal

She eked out a narrow win in the three-way primary then trounced Euille in the general election. In a feat of physical fortitude, she did it while on crutches, having snapped a tendon in her left leg at a tennis clinic during an August vacation.

Because of the injury, she skipped the traditional door-knocking that Alexandria elections usually require, and she relied on a network of friends who let her stay at their homes, cooked her meals, drove her around and collected her mail.

Silberberg, who has never been married and has no children, celebrated the group effort in her political newsletters, saying it demonstrated the deep level of support she has in the city. But there are also deep differences of opinion about the city’s future, as shown by bitter fights in recent years over the pace and scope of development.

As mayor, Silberberg says, she wants to conduct city business more transparently and bring a new tone to political and governmental discourse. She pledged during her campaign to limit closed-door council sessions and push for faster public disclosure of staff memos, and she says she wants council members to stop sending emails to city employees between 7 p.m. and 9 a.m.

“It’s time for a new shared sense of purpose,” Silberberg said. “We should set the standard for family friendliness.”

Silberberg plans to launch an ethics commission to review, among other things, whether city lawmakers should vote on projects involving people who have given them campaign donations. The review would be a not-so-subtle slap at Euille, who was backed by developer and business interests and said it was fine to vote on projects involving donors so long as he disclosed the connection.

She makes no apology for her desire to limit development in Old Town. “This is a remarkable, historic city,” she said. “It’s a serious responsibility. And if we’re not careful, if we’re not long-term thinkers, who will be?”

But during her years on the council, she has struggled to win support for that position from her colleagues. Some have rolled their eyes and turned their attention away when she introduced amendments at the wrong time or used imprecise language. On several occasions, Euille cut her off in an attempt to get the council to move more quickly, or chided her for failing to properly make a motion.

Some of her supporters call such rebukes sexist. But Silberberg declines to go there.

“I don’t see it that way. Others do,” she said. “I show everyone respect. And when it’s not reciprocated, that’s only embarrassing to the person doing that.”

Council member Justin Wilson (D), the incoming vice mayor, declined to discuss past issues on the council, saying he wants to focus on what’s ahead. “Being an individual member of the council is different from being the mayor,” Wilson said. “No matter who the voters have chosen, it’s our job to work together, and I’m sure we will.”

Silberberg, too, would not address the council’s internal dynamics. In multiple interviews, she said she was “deeply honored” by the support she has received and her political experiences so far.

As mayor, she said, she will try to build consensus and focus on what the city needs: “I try really hard to hear what’s being said — and not being said,” she explained.