Judge McKeown was appointed to the United States Court of Appeals for the Ninth Circuit in 1998. She graduated from Georgetown University Law Center and holds an honorary doctorate from Georgetown University. Before her appointment, Judge McKeown was the first female partner at Perkins Coie in Seattle and Washington, D.C., and served as a White House Fellow. Judge McKeown chairs the Ninth Circuit Workplace Environment Committee and is a member of the National Workplace Conduct Working Group and the Judicial Conference United States Committee on Judicial Conduct and Disability. She served as president of the Federal Judges Association, chair of the Judicial Conference United States Codes of Conduct Committee (ethics), and chair of the ABA Commission on the 19th Amendment. She serves on the boards of the World Justice Project and the Teton Science Schools and is on the Council of the American Law Institute, the Judicial Advisory Board of the American Society of International Law, and the editorial board of Litigation magazine.

Judge McKeown is immediate past chair of the ABA Rule of Law Initiative and a current special advisor. She has lectured throughout the world on international law, human rights law, intellectual property, litigation, ethics, judicial administration, and constitutional law and has participated in numerous rule of law initiatives with judges and lawyers. Judge McKeown is a member of the American Academy of Arts and Sciences. She received the ABA Margaret Brent Women Lawyers of Achievement award, the ABA John Marshall Award, and the Girl Scouts Cool Woman Award, among others. Judge McKeown will receive the American Inns of Court Justice Lewis Powell, Jr. Award for Ethics and Professionalism at the Supreme Court in October 2024.

Judge McKeown is the author of Citizen Justice: The Environmental Legacy of William O. Douglas—Public Advocate and Conservation Champion (2022).