[3][4][5] A member of the Democratic Party, Johnson previously served on the Cook County Board of Commissioners from 2018 to 2023, representing the 1st district.

[9] Johnson worked as a social studies teacher at Jenner Academy Elementary and George Westinghouse College Prep, both part of the Chicago Public Schools system.

He was endorsed by a number of labor organizations and progressive advocacy groups, including the Chicago Teachers Union, Grassroots Illinois Action, The People's Lobby, Our Revolution, and SEIU Locals 1 and 73.

[13] In November 2019, Johnson wrote an essay in a CTU publication drawing a distinction between the union's organizing model and "top-down school governance.

[26][27] In the summer of 2020, amid the George Floyd protests, Johnson authored the "Justice for Black Lives" resolution that was adopted in July 2020.

[28][29] The resolution called for reallocating funding "from policing and incarceration" to "public services not administered by law enforcement that promote community health and safety equitably.

[38] In the weeks that followed, he received endorsements from United Working Families,[39] the Chicago Teachers Union,[40] and progressive independent political organizations in the 30th, 33rd, 35th, and 39th wards.

[41] On October 23, the American Federation of Teachers pledged to donate $1 million to Johnson's campaign should he enter the race.

"[47][48][49] His campaign emphasized funding and resources for public schools,[50] a public safety platform that includes efficiency audits and non-police responses to mental health emergencies,[51] support for a real estate transfer tax to fund homelessness response and prevention,[50] and a budget that proposes raising $1 billion in new revenues, including through new or increased taxes on airlines, financial transactions, high-value real estate transfers, and hotels.

[52][53][54] Amid polling showing crime and police relations as the leading issue, Johnson was the only primary candidate who did not express support for hiring more police officers, suggesting instead an increase in the detective force from existing ranks, citywide youth hiring, reopening mental health centers, and investment in violence prevention as means to address 'root causes of crime',[55] in line with voter preferences for increased job training and economic opportunity over force expansion.

[58] Johnson characterized García of having "abandon[ed] the progressive movement” and of having presented no distinction from Mayor Lightfoot in his proposals for combatting violent crime in Chicago.

[45] Johnson further characterized García as having been absent from work on a number of issues that impacted Latino neighborhoods in the city.

"[59] In the closing weeks of the campaign, as Johnson was recognized as a more prominent contender in the race due to a continued rise in polls, he began to face focused criticism from Mayor Lightfoot as well as fellow progressive challengers Kam Buckner and Ja'Mal Green.

On February 8, 2023, a political action committee supporting Mayor Lightfoot began to run an attack ad against Johnson.

Congressman Chuy García and Illinois State Representative Kam Buckner endorsed Johnson in the runoff.

[66] Among the most prominent figures to endorse Johnson in the general election were activist and two-time presidential candidate Jesse Jackson,[67] Cook County Board of Commissioners President Toni Preckwinkle (the runner-up of the previous mayoral election in 2019),[68] Illinois Attorney General Kwame Raoul,[69] former U.S.

[73] Prior to advancing to the runoff, both Johnson and Vallas had come out in opposition to the notion of the city spending $2 billion or more to renovate and build a dome over the Bears' current municipally-owned home stadium, Soldier Field.

[76][77] While Vallas expressed his belief that it is a foregone matter that the Bears will not reconsider a move to Arlington Heights,[76][78] in the runoff Johnson reiterated his previously declared stance that the city should still pursue the opportunity to negotiate with the football team,[79] and pledged that as mayor he would "sit down and work with the [Chicago Bears] ownership", in order to see what arrangement the city and the team, "can figure out".

[95] Approximately a week after his election, Johnson joined a picket line alongside striking faculty members at Chicago State University.

[96] In April 2023, after several large groups of teens and young adults engaged in shootings and vandalism across multiple locations in the city,[97] Mayor-Elect Johnson issued a statement, writing "...in no way do I condone the destructive activity we saw in the Loop and lakefront this weekend.

[101] It was announced that Interim Chief of Police Eric Carter would step down from that position on the day that Johnson is inaugurated.

[104][105][106] As Mayor, Johnson has sought to remove red tape to streamline housing and commercial development in the city.

[111] In 2024, Johnson pushed for a 615-unit apartment building (of which 124 units were affordable housing) on the lot of a former industrial site at 1840 North Marcey Street.

[115] In July 2024, Johnson began suggesting that the school district should take on a new loan in order to cover expenses required to meet the teachers union's demands related to the funding of pensions and contracts.

[115] Amid a standstill, the teachers union publicly lambasted Pedro Martinez, blaming him and pejoratively labeling him a "Lightfoot holdover".

[117] On September 24, the Chicago Tribune published an op-ed by Martinez in which he outlined his reasons for refusing Johnson's request for him to resign.

Soon after he was appointed, attention was brought to a social media post he had made heralding the October 7 Hamas-led attack on Israel as "resistance against oppression", forty members of the city council and governor Pritzker expressed concern, with the governor accusing Mayor Johnson and his administration of failing to properly vet him before appointing him.

The mayor initially defended his school board president, remarking, He recognizes the harm those statements have caused, and has expressed his apology and will continue to seek atonement to have the full confidence in every community in the city of Chicago.

"[130] On February 20, 2024, Johnson as Mayor of Chicago announced lawsuits against major oil and gas companies including BP, Chevron, ConocoPhillips, ExxonMobil, Phillips 66, Shell, and the American Petroleum Institute, accusing them of deceiving the public about the climate change impacts of their products, as the city of Chicago seeks accountability for climate change-related damages it has suffered.

The shooter in question was a Muslim man who was alleged to have screamed "Allahu Akbar" while in a shootout with Chicago police prior to his arrest.