[1][17][18] Lightfoot held positions working for Congress members Ralph Regula and Barbara Mikulski before deciding to attend law school.

During her mayoral campaign, Lightfoot cited several reasons for entering public service, including a desire to represent the African-American community, a sense of injustice based on the murder of a family member by a Ku Klux Klan member in the 1920s, and struggles with the law encountered by her older brother, who was charged with possession of crack cocaine with intent to distribute.

[15] In one notable case, Lightfoot went against Police Department orthodoxy by recommending the firing of officer Alvin Weems, who shot and killed an unarmed man, Michael Pleasance.

[28] In another controversial case where officer Phyllis Clinkscales shot and killed unarmed 17-year-old Robert Washington, the Chicago Tribune reported that Lightfoot determined that the shooting was justified.

Lightfoot and Dempsey's investigations included probes of then-Governor of Illinois Rod Blagojevich's associate Tony Rezko and prominent Daley donor Elzie Higginbottom.

[33] 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.

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.

[35] 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".

The Chicago Board of Elections Commissioners found Lightfoot had enough valid petitions to remain on the ballot, and Preckwinkle's campaign withdrew its challenge.

[58][59] Several former candidates, including Mendoza, Chico, Paul Vallas, and fourth-place finisher Willie Wilson also endorsed Lightfoot in the runoff.

[30][64] Lightfoot defended herself against Bennett's criticisms at a mayoral debate, citing her personal experiences with racial discrimination as evidence she would take the concerns of the black community into account.

[65] Lightfoot also faced activist criticism over comments at a University of Chicago forum where she suggested turning some shuttered schools in the city into police academies.

However, Lightfoot received praise for her efforts to build affordable housing, repair dilapidated areas of the city, and raise the minimum wage.

[72] As mayor-elect, Lightfoot expressed a desire for the Laquan McDonald trial to be reexamined, urging the U.S. Attorney's Office to reopen their grand jury investigation to examine if any civil rights were violated.

[73] 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.

[75] 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.

[83] Many of these recommendations were eventually integrated into the distribution of federal relief funds for housing assistance grants, as well as allocations for low-income tax credits.

[87] After legislation expanding gambling in Illinois was passed by the state legislature at the start of June 2019, Lightfoot announced that the city would commence a study of where a Chicago casino would be located.

[89] On May 5, 2022, Lightfoot announced that she had selected a bid from the Bally's Corporation to construct a casino resort on the west bank of the Chicago River.

[95] Lightfoot's first executive order as mayor limited "aldermanic prerogative", a practice under which Chicago aldermen were granted an effective veto over matters in their wards.

[105][106] On March 15, 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".

[108] Lightfoot's administration supplemented the state response with municipal public health measures, and the mayor leveraged the visibility of her office to promote adherence.

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,[118][119] and her administration worked with the United States Army Corps of Engineers to establish a makeshift hospital at McCormick Place.

"[126] Lightfoot was further scrutinized for her decision to issue new restrictions, including a stay-at-home advisory, on November 12, as she had been seen days earlier at a large gathering celebrating Joe Biden's election victory.

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

[156] In February 2022, it was announced by Lightfoot that Chicago residents would be able to apply to participate in the city's $500-per-month basic income pilot program in April of that year.

[157] The pilot program was offered to Chicago residents who suffered economic hardship due to the COVID-19 pandemic, giving them the chance to enter into a lottery to get $500 monthly payments for the course of one year.

[158] The pilot program was for 5,000 participants and had the requirements of: the applicant must live in Chicago, be at least 18 years old, have experienced economic hardship related to COVID-19, and have a household income at or below 250% of the federal poverty level.

[163] Lightfoot ran ads tying García to Sam Bankman-Fried and Michael Madigan and accusing Johnson of wanting to reduce police budgets.

[208] 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".