Chicago mayor-elect Lori Lightfoot, center, photographed in December 2017 with her former Mayer Brown partners Rajesh De, left, and Andrew Pincus. Photo: Diego M. Radzinschi/ALM

CHICAGO—Lori Lightfoot's victory in the race to be the city's next mayor was historic for a number of reasons. She will be the first black woman and first openly gay person to serve as the city's mayor. And for a city used to seeing its public officials in trouble with federal prosecutors, Lightfoot's past as an assistant U.S. attorney may have been viewed as refreshing by many voters.

Lightfoot is also a former Mayer Brown partner who gave up Big Law life last year to pursue her upstart, progressive mayoral campaign—vowing to invest in schools, neighborhoods and violent streets that she said were long overlooked by the city's powerful political class in favoring of its shimmering downtown business quarter.

“We were up against powerful interests, a powerful machine and a powerful mayor,” Lightfoot said in a victory speech Tuesday, after securing nearly 75 percent of votes to defeat fellow Democrat Toni Preckwinkle in a runoff election to succeed Mayor Rahm Emanuel.

Paul Theiss, Mayer Brown's chair, said in an interview that the firm fully supported Lightfoot's decision to leave the firm for her campaign and that the firm was excited that the former co-leader of its commercial litigation practice had won. Lightfoot had also served as co-chair of the firm's diversity and inclusion committee.

“Lori has been a great colleague of ours at Mayer Brown and made a big difference at the firm,” Theiss said. “She always conducted herself with a very high level of integrity and always had great ideas with how to solve client problems. And I expect she'll have great ideas for how to solve the challenges of the city as well.”

While there have been few specifics regarding how Lightfoot plans to address Chicago's long-term debt issues, she did muse on the campaign trail that the city might want to look toward what may be an unexpected group of businesses to generate revenue: Large, international law firms like Mayer Brown.

Lightfoot made local headlines in late March when she said in a radio interview that large law firms and accounting firms could be subjected to a special tax.

“One of the things that I propose is a tax on high-end law firms and accounting firms akin to the VAT—the value added tax—in Europe,” Lightfoot said in the interview. “Not on the little guys, not on the solo practitioners or small CPA firms. But a firm like mine, which is a large, international law firm. Putting a small fee on the invoices they send their clients will barely be noticed yet could generate hundreds of millions of dollars in revenue. Those are the kinds of things that we need to think about.”

Lightfoot's campaign did not immediately respond Tuesday to a request for more details on that potential plan.

While Lightfoot is a first-time political candidate, she has held roles in city government before.

Most notably, she was appointed in 2015 to lead a task force reviewing police accountability following public outrage over the delayed release of a video showing teenager LaQuan McDonald being shot 19 times by a Chicago Police Officer. The officer, Jason Van Dyke, has since been found guilty of second-degree murder.

The report Lightfoot's task force released in April 2016 was viewed as a scathing indictment of the city's police department. It said racism in the department compromised the police's integrity among minority communities, noting that 74 percent of civilians Chicago police shot between 2008 and 2015 were black.

Among the policy recommendations in Lightfoot's report was the creation of a community safety oversight board that would have a role in police disciplinary proceedings.

Vince Connelly, a longtime colleague of Lightfoot's as a Mayer Brown partner, said Lightfoot was always interested in advancing civic issues she viewed as important. Still, he had not heard her express interest in running for public office before she launched her campaign. Now that she is in public office, Connelly said he hoped she brought the same team-oriented approach to politics that she used as a lawyer preparing for trial.

“She always tried to surround herself with as many good people as was needed to get the task done,” Connelly said. “She was never afraid to look for talent and she was never afraid to listen to talent. I'm hoping that skill set will serve her and the city well.”

While Lightfoot celebrates her victory, another Mayer Brown partner with political ambitions recently suffered a loss. German-based senior counsel Friedrich Merz in December lost a run-off election to lead the Christian Democratic Union party that has been headed by departing German Chancellor Angela Merkel for nearly two decades.