Kati Marton was born Katalin Ilona Marton in Budapest, Hungary. Her parents were award-winning journalists Ilona Marton (UPI) and her husband Endre Marton (Associated Press). The elder Martons survived the Holocaust in World War II but never talked about it or their Jewish roots to their children. Kati and her sister grew up as Roman Catholics, speaking French and Hungarian. They were placed in the care of strangers when their parents were imprisoned on charges of espionage by the Communist regime. The family had to flee Hungary following the Hungarian uprising of 1956 and settled in Chevy Chase, Maryland, where Kati attended Bethesda-Chevy Chase High School.
She studied at the Sorbonne and the Institut d'Études Politiques in Paris. She earned a master's degree in International Relations from George Washington University.
She married as her second husband Peter Jennings, news anchor for ABC-TV, with whom she had two children before divorcing in 1993.
Her third husband was diplomat Richard Holbrooke. She also became a prize-winning reporter for ABC News, CBS, and NPR, receiving the George Foster Peabody Award in 1973. Among her works is Wallenberg: The Incredible True Story of the Man Who Saved the Jews of Budapest (2011). Her first memoir, Enemies of the People: My Family's Journey to America (2009), was a finalist for the National Book Critics Circle Award. She also wrote Paris: A Love Story (2012) about the years of her marriage to Holbrooke, who died in 2010.