The Supreme Court released its final merit opinions on the morning of June 30, 2022. At noon, Breyer officially retired and Jackson was sworn in, becoming the first Black woman and the first former
federal public defender to serve on the Supreme Court. On September 28, 2022, Jackson was assigned as the circuit justice for the
First Circuit. On July 21, Jackson voted on her first Supreme Court case, joining the dissent in a 5–4 decision refusing to block a district court ruling that prevented the Biden administration from setting new enforcement priorities for immigrants entering the United States or living in the country illegally. She participated in her first oral argument as an associate justice on October 3, in
Sackett v. Environmental Protection Agency. On November 7 she wrote her first opinion, a two-page dissent from a denial of review in the case of a death row inmate in
Chinn v. Shoop; the opinion was joined by Justice Sotomayor. Two contributors to
SCOTUSBlog noted that, since joining the Court at the beginning of the 2022 term, Jackson was the most active participant in oral arguments, speaking an average of 1,350 words per argument, while the eight other justices each spoke on average fewer than 1,000. On February 28, 2023, Jackson authored her first majority opinion for a unanimous court in
Delaware v. Pennsylvania, which involved how unclaimed money from
MoneyGrams are distributed among individual states. In 2025, Justice
Amy Coney Barrett criticized Jackson's dissent in
Trump v. CASA, writing, "Justice Jackson decries an imperial Executive while embracing an imperial Judiciary." On July 8, 2025, in
AFGE v. Trump, the Supreme Court issued an emergency order on Trump's federal workforce reorganization, ruling in Trump's favor 8–1, with Jackson the lone dissenter. It was an appeal of a lower court ruling in the Northern District of California. Jackson argued that Trump's reorganization of the United States government was an illegal restructuring of the federal bureaucracy. Justice
Sonia Sotomayor said the case was not about the merits of the reorganization plans themselves and pointed out that the case could proceed and other aspects challenged.
Labor disputes On June 1, 2023, Jackson wrote the sole dissenting opinion in
Glacier Northwest, Inc. v. Teamsters, concerning the power of employers to sue labor unions regarding the destruction of employer property following a
strike. In her opinion, she argued that further deference to the
National Labor Relations Board was justified given the precedent of cases such as
San Diego Building Trades Council v. Garmon that stipulate that the
NLRA preempts state law when the two conflict. Jackson further contended that the majority opinion failed "Congress's intent with respect to the Board's primary role in adjudicating labor disputes", with its deference to state actions risking "erosion of the right to strike". In her conclusion, she emphasized these points, writing: "Workers are not indentured servants, bound to continue laboring until any planned work stoppage would be as painless as possible for their master. They are employees whose collective and peaceful decision to withhold their labor is protected by the NLRA even if economic injury results". On June 13, 2024, Jackson wrote an opinion, concurring in part and dissenting in part, in
Starbucks Corporation v. McKinney. In it, she agreed that the case should be reheard in the lower courts using the four criteria tests of
Winter v. Natural Resources Defense Council, but argued that the majority failed to follow the NLRA's directives of court deference to NLRB authority in labor disputes. Arguing that the court was failing to issue proper deference to the NLRB, Jackson wrote, "I am loath to bless this aggrandizement of judicial power where Congress has so plainly limited the discretion of the courts, and where it so clearly intends for the expert agency it has created to make the primary determinations".
Affirmative action Jackson dissented from the Supreme Court's ruling in
Students for Fair Admissions v. University of North Carolina, the companion case to
Students for Fair Admissions v. President and Fellows of Harvard College, which limited the use of racial preferences in university admissions. In her dissent, Jackson emphasized the relationship between
Black Americans and the United States government, writing, "Our country has never been colorblind", and associating
affirmative action as a corrective marker in reconciliation. In doing so, she expressed opposition to the majority's usage of the
Equal Protection Clause, writing, "To impose this result in that Clause’s name when it requires no such thing, and to thereby obstruct our collective progress toward the full realization of the Clause’s promise, is truly a tragedy for us all".
Judicial philosophy Jackson has said she does not have a particular judicial philosophy, but rather has a perspective on legal analysis or a "judicial methodology". Though she has not embraced the label, Jackson has expressed that she sees value in
originalism, saying the "Constitution is fixed in its meaning", and has explicitly criticized
living constitutionalism. According to Sahil Kapur, writing for
NBC News, "Jackson fits well with the Democratic Party and the progressive movement's agenda" due to her relative youth, background as a public defender, and history of labor-friendly rulings.
Politico reported that "Jackson is popular with liberal legal activists looking to replace Breyer with a justice willing to engage in ideological combat with the court's conservatives." == Personal life ==