After accompanying her father on a business trip to Chicago and visiting Northwestern University, she would later attend the school on a scholarship, graduating in 1986 with a bachelor's degree in communications.

[12] While John was a member of Congress, McClain Delaney served as the chair of the Congressional Club's First Lady Luncheon and was a co-chairwoman for the National Prayer Breakfast.

She received support from former Speaker of the House Nancy Pelosi during her primary campaign, as well as the United Auto Workers labor union and The Washington Post.

[17] Opposing primary candidate Joe Vogel, who was described by Maryland Matters as a frontrunner in the race alongside McClain Delaney,[18] criticized her use of private loans to fund the campaign, accusing her of "buy[ing] her way to victory."

[22] In the general election, McClain Delaney highlighted her experience in the U.S. Department of Commerce and criticized Parrott's stances on abortion, antisemitism, and LGBTQ issues.

[4] McClains Delaney supports the Blueprint for Maryland's Future,[34] universal pre-kindergarten, free community college, and expanding skills training programs in schools.

[35] McClain Delaney supports increasing funding for the United States Environmental Protection Agency[34] and climate science research, as well as providing tax incentives for investments in decarbonization technologies.

[22] She also supports cutting regulations for affordable housing construction, reinstating the child tax credit,[38] and using antitrust laws to foster competition between grocery companies.

[39] McClain Delaney has blamed both Democrats and Republicans for increases to the national debt of the United States and expressed support for deficit reduction through strategic budget cuts, waste elimination, and reforms to Social Security, Medicare, and Medicaid.

[36] McClain Delaney supports strengthening NATO, promoting U.S. economic interests abroad, and leading on issues like climate change to counter foreign policy challenges from China, Russia, and the Middle East.

She also condemned anti-Israel rhetorics on college campuses and supported calls by New York Attorney General Letitia James for increased moderation on social media platforms to remove hate speech and propaganda associated with the Hamas attacks.

[43] In January 2025, McClain Delaney was one of 45 Democrats to vote for a bill to place sanctions on the International Criminal Court for issuing arrest warrants against Benjamin Netanyahu and former Israeli Defense Minister Yoav Gallant.

[44] During her 2024 congressional campaign, McClain Delaney supported "common sense gun legislation" such as universal background checks, assault weapon bans, and red flag laws.

[2] During her 2024 congressional campaign, McClain Delaney supported efforts to codify the Roe v. Wade decision, including the Women's Health Protection Act.