[16] After high school, Jackson matriculated at Harvard University to study government, having applied despite her guidance counselor's advice to set her sights lower.

[25] She spent a year in private practice at the Washington, D.C., law firm of Miller Cassidy Larroca & Lewin (now part of Baker Botts), then clerked for Justice Stephen Breyer from 1999 to 2000.

[29] From 2005 to 2007, Jackson was an assistant federal public defender in Washington, D.C., where she handled cases before the United States Court of Appeals for the District of Columbia Circuit.

[30] A review by The Washington Post of cases Jackson handled during her time as a public defender showed that "she won uncommon victories against the government that shortened or erased lengthy prison terms".

[37] On September 20, 2012, Obama nominated Jackson to serve as a United States district judge for the District of Columbia to the seat vacated by retiring judge Henry H. Kennedy Jr.[38] Republican U.S. Representative Paul Ryan, a relative by marriage, introduced Jackson at her December 2012 confirmation hearing and said, "Our politics may differ, but my praise for Ketanji's intellect, for her character, for her integrity, it is unequivocal.

In her opinion ordering Trump's former White House counsel Don McGahn to comply with a legislative subpoena, she wrote that "presidents are not kings".

[42] Bloomberg Law reported in spring 2021 that conservative activists were pointing to certain decisions by Jackson that had been reversed on appeal as a "potential blemish on her record".

"[47] In April and June 2018, Jackson presided over two cases challenging the Department of Health and Human Services' decision to terminate grants for teen pregnancy prevention programs two years early.

[51][52] In 2018, Jackson dismissed 40 wrongful death and product liability lawsuits stemming from the disappearance of Malaysia Airlines Flight 370, which had been combined into a single multidistrict litigation.

[53][54][55][56] In 2019, in Center for Biological Diversity v. McAleenan, Jackson held that Congress had, through the Illegal Immigration Reform and Immigrant Responsibility Act, stripped federal courts of jurisdiction to hear non-constitutional challenges to the United States Secretary of Homeland Security's decision to waive certain environmental requirements to facilitate construction of a border wall on the United States and Mexico border.

[58] She found that the U.S. Department of Homeland Security had violated the Administrative Procedure Act (APA) because its decision was arbitrary and capricious and the agency did not seek public comment before issuing the rule.

Circuit reversed the entry of the preliminary injunction, ruling that the IIRIRA (by committing the matter to the executive branch's "sole and unreviewable discretion") precluded APA review of the decision.

[65][66][67][68] Noting that she took four months to resolve the case, including writing a 120-page opinion, The Washington Post wrote: "That slow pace contributed to helping Mr. Trump run out the clock on the congressional oversight effort before the 2020 election.

[26] During her time on the Circuit Court Jackson authored two majority opinions, American Federation of Government Employees v. FLRA and Wye Oak Technology, Inc. v. Republic of Iraq.

[83][85] In Wye Oak Technology, Inc. v. Republic of Iraq Jackson wrote for a unanimous panel regarding the Foreign Sovereign Immunities Act's commercial activity exemptions.

[86] In her opinion, Jackson addressed prior litigation by Wye Oak Technology which had determined that, under the second of the Act's three exemption clauses, U.S. courts were permitted to exercise jurisdiction over Iraq to facilitate the payment of their invoices.

[91] In early 2016, Obama administration officials vetted Jackson as a potential nominee to the Supreme Court of the United States to fill the vacancy left by the death of Justice Antonin Scalia.

[95] In early 2022, news outlets speculated that Biden would nominate Jackson to the U.S. Supreme Court to fill the seat vacated by Justice Breyer.

[96][97][98][99] Biden pledged during the 2020 United States presidential election campaign to appoint a black woman to the court should a vacancy occur.

[117] Republicans Mitt Romney, Lisa Murkowski, and Susan Collins joined all Democrats in confirming Jackson to the Supreme Court.

At noon, Breyer officially retired and Jackson was sworn in, becoming the first Black woman[14][12] and the first former federal public defender to serve on the Supreme Court.

[131] 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.

[133] 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.

[134][135] 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".

[136] 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.

[143] In her dissent, Jackson emphasized the relationship between Black Americans and the U.S. government, writing, "Our country has never been colorblind", and associating affirmative action as a corrective marker in reconciliation.

[151] 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.

[152] 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.

[154] He is a descendant of Continental Congress delegate Jonathan Jackson[155] and is related to U.S. Supreme Court Justice Oliver Wendell Holmes Jr.[156] The couple have two daughters.

Years later, Jackson persuaded a law firm to take his case pro bono, and President Barack Obama eventually commuted his sentence.