[6] With the support of the local chapter of the Democratic Socialists of America (DSA),[7] Lee was also the first black woman to represent Southwestern Pennsylvania in the state legislature.

[6] Of African American heritage, Lee was raised in North Braddock, Pennsylvania, and attended Woodland Hills High School.

An organizer from Pittsburgh's DSA chapter approached her about running after she led a successful write-in campaign for a school board candidate.

[21] Amid concerns that her criticism of Israel could cost her renomination in a district with a significant Jewish population, Lee cultivated endorsements from prominent Democrats including House Minority Leader Hakeem Jeffries and Senator Bob Casey Jr.[22] The race between Lee and Patel, who is pro-Israel, was seen as a bellwether for other primary races where pro-Israel candidates are challenging progressive, Israel-critical incumbents.

[28] Lee joined forty other House Democrats in a letter calling on the Biden Administration to use all means possible to preserve FDA approval for Mifepristone and protect access to these treatments nationwide, in response to a ruling by Northern District of Texas Judge Matthew Kacsmaryk.

[29][30] In response to the Supreme Court's decision in Students for Fair Admissions v. Harvard, which held that race-based affirmative action programs in college admissions processes violate the Equal Protection Clause of the Fourteenth Amendment, Lee stated that she was "disgusted that our country just enshrined racial inequity in higher education and economic immobility into law.

[34] On March 29, 2023, two Pittsburgh Catholic schools received what investigators deemed were hoax active shooter threats that prompted evacuations, lockdowns and large responses from police.

[42] In response to these events, Lee publicly supported multiple bills in Congress that look to enforce strict regulations on the rail industry.

[43] She is an original co-sponsor of the DERAIL Act, which would put stricter federal rail safety regulations in place that were rolled back during the Trump administration.

"[50][51][52] On June 13, 2023, Lee was one of 13 representatives (eleven Democrats and two Republicans) who voted against a bill mandating the Biden administration appoint a special envoy for the Abraham Accords.

Whether we're talking about India, Israel, or Sri Lanka, we are not true allies if we cannot push our partners to uphold basic human rights & democratic values.

[62][63] In light of a potential ban on TikTok in the United States, Lee has supported the platform, calling it "an incredible organizing tactic.