Lightfoot received her Bachelor of Arts in political science from the University of Michigan in 1984, graduating with honors. She pursued seven different types of employment to pay for her education, including working as a resident assistant and as a cook for the school’s football team. She also held factory jobs at home during summers to help pay for her education. While Lightfoot was an undergraduate, her older brother was arrested in connection with a bank robbery.

Lightfoot held positions working for Congress members Ralph Regula and Barbara Mikulski before deciding to attend law school. She has said she chose to attend law school not because of her brother’s legal troubles, but because she wanted a job that offered financial independence. She matriculated at the University of Chicago Law School, where she was awarded a full scholarship. As president of the University of Chicago Law School’s student body, she led a successful movement to ban a law firm from campus after the firm sent a recruiter who made racist and sexist remarks towards a student. Lightfoot quarterbacked an intramural flag football team while at Chicago Law School. Lightfoot also served as a clerk for Justice Charles Levin of the Michigan Supreme Court. She graduated from the University of Chicago with her Juris Doctor degree in 1989.

While working as a federal prosecutor, Lightfoot helped to prosecute those accused of federal crimes, including drug crimes. She assisted with Operation Silver Shovel, an FBI investigation into Chicago corruption. She helped to convict alderman Virgil Jones. In 1999, Lightfoot was issued a warning for misconduct by judge Richard Posner in a case in which she was found by the United States Court of Appeals for the Seventh Circuit to have misled a United States Circuit Judge regarding a suspect’s whereabouts, making it impossible for the judge to stay the suspect’s extradition to Norway. Lightfoot and the Justice Department at the time disputed this characterization of her actions.

In 2002, Lightfoot was appointed chief administrator of the Chicago Police Department Office of Professional Standards, a now-defunct governmental police oversight group, by Police Superintendent Terry Hillard. She held the position for two years. In the position, she was in charge of investigating possible cases of police misconduct, including police shootings of civilians. However, a Chicago Tribune report found that the Office of Professional Standards’ investigations often lacked thoroughness. Lightfoot says her recommendations for disciplinary action were often rejected by the police department.

She is a graduate of Washington High School in Massillon, where she was a trumpet player in the school band, point guard on the basketball team, yearbook editor, and Pep Club member. She was elected high school class president three times. Her high school alumni association named her a “Distinguished Citizen” in 2013. While in high school, Lightfoot helped organize a boycott of her school’s lunch program over the quality of its pizza.

Lightfoot has also served on the boards of the Illinois chapters of NARAL and the ACLU. She has served as external counsel for Bank of America. In 2013, Lightfoot was a finalist for the position of U.S. Attorney for the Northern District of Illinois, but the job went to Zachary T. Fardon.

Lightfoot returned to the public sector in 2015, when Mayor Rahm Emanuel appointed her to replace 19-year incumbent Demetrius Carney as President of the Chicago Police Board. The board’s main responsibility is to make recommendations for or against disciplinary action on certain disputed cases of police misconduct. Under Lightfoot’s leadership, the board became more punitive, firing officers in 72% of its cases. In the wake of the controversy over the murder of Laquan McDonald, Emanuel also appointed Lightfoot as Chair of a special Police Accountability Task Force. In 2016, the Task Force, led by Lightfoot, filed a report critical of the Chicago Police Department’s practices. She specifically criticized the police union’s “code of silence.” The anti-police brutality activist organization Black Youth Project 100’s Chicago chapter released a statement denouncing Lightfoot and the Board and Task Force for a “lack of accountability.”

In 2017, Emanuel re-appointed Lightfoot to a second term as president of the Police Board. The decision came after Lightfoot and Emanuel had publicly come into conflict, particularly over Emanuel’s attempts to reach a police reform deal with Trump Administration Justice Department officials that would avoid a consent decree and oversight from a federal judge. Lightfoot called Emanuel’s approach “fundamentally flawed.” At the time, there was already speculation that Lightfoot was planning a run for mayor of Chicago in 2019, though she denied the rumors. Lightfoot resigned from the Police Board in May 2018, just before announcing her mayoral campaign.

On May 10, 2018, Lightfoot announced her candidacy for Mayor of Chicago in the 2019 elections, her first-ever run for public office. She is the first LGBTQ mayor and first black female mayor of Chicago. Lightfoot was the first openly lesbian candidate in the history of Chicago mayoral elections.

By summer 2018, Lightfoot had the highest-funded campaign of any individual challenging the two-term incumbent Emanuel. However, in the fall, Emanuel dropped out of the race, and high-profile candidates like Gery Chico, Bill Daley, Susana Mendoza and Toni Preckwinkle subsequently entered.

As an attorney at Mayer Brown, Lightfoot represented Republicans in two cases protesting Democratic gerrymandering. At Mayer Brown, she also defended Chicago police officer Paul Powers against charges of physical assault. In 2019, after facing criticism over defending Powers, Lightfoot cited video evidence in favor of her former client’s innocence.

Lightfoot won the runoff election on April 2, 2019, becoming mayor-elect of Chicago. She won more than 73% of the overall vote in the runoff, winning in all 50 wards of the city. Lightfoot won all but 20 of the city’s 2,069 voting precincts. Voter turnout was 32.89%, almost a record low.

Lightfoot took office on May 20, 2019. Incumbent mayor Rahm Emanuel reportedly modeled the transition between his and Lightfoot’s administrations on the U.S. presidential transition between the George W. Bush and Barack Obama administrations. Emanuel was part of the Bush-Obama transition as Obama’s Chief of Staff designate. Lightfoot endorsed the comparison between her transition and the Bush-Obama transition.

On April 6, 2019, Lightfoot told the Chicago Sun-Times that her staff would, during her first post-election weekend, spend time examining the city’s 600-page agreement with Sterling Bay regarding the Lincoln Yards development. During her campaign, Lightfoot had been critical of the process that was being taken to reach the agreement. The following Monday, at her request, Mayor Rahm Emanuel postponed City Council votes on the approval of $1.6 billion in tax increment financing subsidies for both the Lincoln Yards and The 78 mega-developments. After the developers of the two projects agreed to increase commitments to hiring minority-owned and women-owned contractors, Lightfoot announced that she now supported the deals, which were approved one day subsequent to her declaration of support.

On May 20, 2019, Lightfoot officially took office as Mayor of Chicago, after being sworn in at 11:15 am by Magistrate Judge Susan E. Cox of the U.S. District Court for the Northern District of Illinois, at the Wintrust Arena, accompanied by her wife and daughter.

On October 14, 2019, Lightfoot announced the creation of an affordable housing task force set to consist of 20 members and study solutions to housing affordability over a 4 to 6 month period. The following month, it would be announced that the task force would also come up with a proposal to rewrite the city’s affordable housing ordinance.

On May 28, 2019 Lightfoot unveiled proposals to revise the operating rules of the Chicago City Council. Among other things she proposed live streaming video of committee meetings, changes to strengthen the rule on conflicts of interest and the transfer of control over TIF subsidies to the Council’s Committee on Economic and Capital Development.

Lightfoot has butted heads with embattled Alderman Ed Burke. On May 29, 2019, during the first City Council meeting, over which Lightfoot presided, she held her ground in debating issues with Alderman Burke. On May 31, after indictments were brought against Burke, Lightfoot called for his resignation.

On June 5, 2019, Lightfoot outlined further ethics reform proposals for the City Council.

On June 3, 2019, Lightfoot announced her selections for the Chicago Public Schools school board, appointing former City Clerk of Chicago Miguel del Valle as its president. She also announced that incumbent Chicago Public Schools CEO Janice Jackson would retain her position, having previously only committed to retaining her for an interim period.

In October 2019, Lightfoot dealt with a public schools strike led by the Chicago Teachers Union and Service Employees International Union.

On May 28, 2019 Lightfoot outlined plans to remedy the city’s fines and fees programs, increase its minimum wage to $15 an hour by 2021.

On November 26, 2019, the Chicago City Council approved Lightfoot’s budget for the 2020 fiscal year.

On May 28, 2019, Lightfoot outlined a plan to focus on reducing the city’s gun violence.

On May 28, 2019, Lightfoot urged City Council to pass an ordinance within her first hundred days that would establish a level of civilian oversight on the Chicago Police Department.

Lightfoot launched a community policing initiative in June 2019. Later that month she announced that the city’s police department would not assist U.S. Immigration and Customs Enforcement (ICE) raids, denying ICE access to the city’s police database in an effort to protect the city’s immigrant population from the threat of deportation.

On November 8, 2019, after Eddie T. Johnson announced that he would resign from his position as Superintendent of the Chicago Police Department, Lightfoot named Charlie Beck to serve as interim Superintendent of the Chicago Police Department. On December 2, rather than letting Johnson voluntarily retire, Lightfoot fired him due to what she declared were “intolerable” actions by him and him misleading the public. Lightfoot nominated David Brown to be Superintendent of Police on April 2, 2020. After Beck stepped down on April 15, Brown became acting Superintendent, while pending confirmation to serve on a permanent basis.

On November 13, 2019, Lightfoot proposed an ordinance that would create a new Office of Public Safety Administration, which would combine administrative functions of Chicago Police Department, the Chicago Fire Department and the Office of Public Safety Administration. The ordinance would also move the task of hearing appeals from rejected Chicago police applicants whose names have been removed from the department’s eligibility list from the Human Resources Board to the purview of the Chicago Police Board.

On May 20, 2019, Lightfoot announced the retention of several administrators who had worked under the previous Emanuel administration, alongside a number of new hires.

On June 3, 2019, Lightfoot announced her selections for the Chicago Public Schools school board, appointing former City Clerk of Chicago Miguel del Valle as its president. She also announced that incumbent Chicago Public Schools CEO Janice Jackson would retain her position, having previously only committed to retaining her for an interim period.

On September 30, 2019, Lightfoot hired former alderman John Arena as a special advisor in the city’s planning department.

In November 2019, Lightfoot named Charlie Beck to serve as interim Superintendent of the Chicago Police Department. On December 2, 2019, rather than allowing Superintendent of the Chicago Police Department Eddie T. Johnson to voluntarily retire, as he had planned to do, Lightfoot fired him due to what she declared were “intolerable” actions by him and him misleading the public. Lightfoot nominated David Brown to be Superintendent of Police on April 2, 2020. After Beck stepped down on April 15, Brown became acting Superintendent, while pending confirmation to serve on a permanent basis.

In December 2019, Lightfoot nominated Gia Biagi to serve as the Commissioner of the Chicago Department of Transportation. Biagi was confirmed by the Chicago City Council to the position on January 15, 2020.

On May 28, 2019, Lightfoot laid out plans to pass “fair work week” legislation tightening rules surrounding workplace scheduling.

On November 26, 2019, the City Council approved ordinances Lightfoot had put forth placing restrictions on vehicle impoundment and lowering fines for illegal possession of cannabis.

In June 2020, Lightfoot voiced her opposition to an ordinance proposed by alderman Roderick Sawyer, which would end the Chicago Public Schools’ contract to station Chicago Police Department officers at schools.

On May 31, 2020 Chicago had 18 Murders, the highest total in 60 years in one day under her administration.

Amid the 2020 coronavirus pandemic in the United States, Lightfoot is taking a number of actions aimed at quelling the severity of the outbreak in Chicago. On March 11, 2020, Lightfoot joined Illinois Governor J. B. Pritzker to announce the postponement of the city’s formal Saint Patrick’s Day festivities (including parades and the dyeing of the Chicago River). On March 12, 2020, Lightfoot again joined Pritzker to announce new mandates which, among other things, banned events attended by more than 1,000 people from being held over the next 30 days.

On March 15, 2020, Lightfoot criticized the long lines at Chicago’s O’Hare International Airport as a result of federal government travel restrictions related to the coronavirus pandemic as “utterly unacceptable”. Under the federal government’s travel restrictions, authorized passengers could only take flights from 26 permitted European nations to a total of thirteen permitted United States airports, of which O’Hare was one. The same day, Lightfoot also announced that, due to concerns surrounding Saint Patrick’s Day festivities, the city would enforce that all businesses selling liquor must have less than half of their regular maximum capacity, and must additionally not exceed a capacity of 100 people.

On March 20, 2020, Lightfoot extended Chicago Public School closures beyond what had already been mandated by the State of Illinois. Chicago Department of Health Commissioner, Dr. Allison Arwady, had signed a public health order under which those with the COVID-19 illness or exhibiting symptoms, with few exceptions, could not leave their place of residence, go to work or any group settings. The order allowed sick residents to seek essential services, such as necessary clinical care/evaluation, and life sustaining needs, such as medicine and food. Lightfoot declared that anyone who violated this order may be issued a citation.

On March 31, 2020, Lightfoot announced that she had secured 300 hotel rooms in the city’s downtown to house first responders, which they could use so that they would not need to go to their homes and risk spreading COVID-19 to their families.

On November 12, 2020, to be effective on November 16, Lightfoot issued new restrictions, including a stay-at-home advisory. Lightfoot was scrutinized for this decision as she had been seen in prior days at a large gathering celebrating Joe Biden’s election victory.

During the 2020 Black Lives Matter (BLM) anti-police violence protests sparked by the killing of George Floyd; Lightfoot, who has a long history of fighting for police reform, stated that police unions have continued to be one of the main obstacles to reform of the department:

In August 2020, she came under criticism for not allowing protests on the block where she lives. Lightfoot said this was justified because she had received threats.

On March 6, 2020, Lightfoot named Tracey Scott as her pick to serve as CEO of the Chicago Housing Authority. On March 30, the CHA Board of Commissioners approved Tracey Scott’s appointment.

On March 6, 2020, shortly before the 2020 Illinois Democratic presidential primary, Lightfoot endorsed Joe Biden’s candidacy for president.

In June 2020, in honor of the 50th anniversary of the first LGBTQ Pride parade, Queerty named her among the fifty heroes “leading the nation toward equality, acceptance, and dignity for all people”.