On the city council, she represented District 4, which includes parts of Boston's Dorchester, Mattapan, Jamaica Plain, and Roslindale neighborhoods.

[9][7] Campbell was raised in the Roxbury and South End neighborhoods of Boston in an area that is a key black population and cultural center of the city.

[19] In 2016 Campbell and Councilor Ayanna Pressley introduced an ordinance that would have banned the use of credit scores by employers to negatively assess job applicants and existing hires.

[26] Also in 2019, Campbell and fellow councilor Matt O'Malley proposed the idea of a vacancy tax on abandoned residential and commercial properties.

Campbell denied that her proposal was in response to Garrison, instead claiming it came from a belief that giving a seat to someone who had not outright won election to it is undemocratic.

Campbell was critical of the event and the public resources that went to providing crowd control and security around it, writing, "while I am a firm believer in free speech, I’m not okay with wasting tens of thousands of taxpayer dollars for a group to come into Boston from out of state to create chaos and spread hate.

[35] In June 2020, Campbell was one of the five city councilors in the minority that voted against Mayor Walsh's $3.61 billion operating budget proposal.

[36] In July 2020, amid the George Floyd protests, Campbell proposed an ordinance to create a police oversight board.

[41] In April 2021, in her capacity as chair of the public safety committee, Campbell refused to push forward $1.2 million in proposed grants for the Boston Police Department.

Amid this, she engaged in a social media conflict with the account of the Boston Police Patrolmen's Association, which had issued criticism of Campbell.

[15] In May 2021, the City Council passed an ordinance by Campbell and Ricardo Arroyo which limits the use of crowd control weapons by officers of the Boston Police Department.

[43] Another such ordinance authored by Campbell and Arroyo had previously been passed by the City Council in December 2020, but had been vetoed by Mayor Marty Walsh in January 2021.

[44][45][46][47] Pressley voiced opposition to the police department's use of exams which she contended were "biased" in order to weigh promotions of officers.

[48] As of January 2020[update], Campbell served on several council committees, including Community Preservation Act, Public Safety & Criminal Justice, Rules and Administration, and Whole.

[56] Campbell's campaign platform included a proposal to reallocate ten percent of the Boston Police Department's budget ($50 million) to other programs matters related to public health, economic justice, and youth issues.

[57] The latter accusation was seen as alluding to the fact that a super PAC supporting Campbell's candidacy received funding from wealthy charter school proponents, such as Reed Hastings.

[60] Following her loss, Campbell stated that she would have a publicly transparent process in contemplating which general election candidate (Annissa Essaibi George or Michelle Wu) to endorse, if any.

She pledged that she would use the office to address matters such as disparities of health and economics negatively impacting the rural parts of the state prison reform, and juvenile justice.

[6] After the Dobbs v. Jackson decision by the United States Supreme Court overturned the federal protections of abortion rights that had been previously protected by the Roe v. Wade decision, Campbell pledged that as attorney general she would establish a reproductive justice unit under the Office of the Attorney General.

[72] In early December, Campbell announced that she had established a committee to facilitate her end of the Attorney General's Office's transition of leadership.

[80] In March 2023, Campbell threatened legal action against Massachusetts Bay Transportation Authority municipalities that were not adhering to the transit-oriented housing policy of the MBTA Communities Zoning Law.

[81] The law, adopted in 2021, requires all municipalities within the service area of the MBTA transit agency to have at least one zoning district permitting multi-family housing by right.

Earlier that month, the town's voters had voted in a referendum against adopting new zoning that would allow multifamily housing in the manner that the law requires.

[86][87] In April 2024, Campbell had the state of Massachusetts join a multi-state lawsuit seeking to reinstate protections for transgender individuals and other vulnerable populations.

[90] In October 2023, months after the United States Supreme Court's Students for Fair Admissions v. Harvard decision declared race-based college admissions affirmative action programs to be unconstitutional, Campbell and Governor Healey jointly released new statewide guidelines for colleges and university's to promote campus diversity.

[94] In December 2023, Campbell launched civil rights litigation against the National Socialist Club 131, a regional neo-Nazi organization.

[76] Her 2022 campaign for attorney general received endorsements from the abortion rights advocacy groups Planned Parenthood, EMILY's List, NARAL Pro-Choice America, and Reproductive Equity Now.

Saying that the ruling, "undermine[s] and discount[s]" the history of the United States, Campbell remarked, Race at the outset was used to marginalize and exclude Black residents, for example, from accessing all types of benefits, some of that perpetuated by the Supreme Court itself.

[110]After the case, Campbell partnered with Governor Healey to create new state guidelines for colleges and university's promotion of diversity.

Campbell has often discussed traumas such as the death of her mother, childhood absence of her father, and her experience in foster care, as well as her twin brother's life story.