Born in Brooklyn, New York, she received her undergraduate degree from Brooklyn College in 1942 and her doctorate from the University of Chicago in 1950. She also studied at the Jewish Theological Seminary of America in New York and at Girton College, Cambridge University. In 1942, she married Irving Kristol, known as the "godfather" of neoconservatism, and has two children, Elizabeth Nelson and William Kristol, a political commentator and editor of The Weekly Standard. Her late brother, Milton Himmelfarb, was a prominent writer on Jewish subjects.

Now Professor Emeritus at CUNY Graduate Center, she is the recipient of many awards and honorary degrees. She has served on the Council of Scholars of the Library of Congress, the Council of Academic Advisors of the American Enterprise Institute, and the Council of the National Endowment for the Humanities. She is a Fellow of the British Academy and of the American Academy of Arts and Sciences. In 1991 she delivered the Jefferson Lecture under the auspices of the National Endowment for the Humanities, and in 2004 she received the National Humanities Medal awarded by the President.

Himmelfarb has argued "for the reintroduction of traditional values (she prefers the term 'virtues'), such as shame, responsibility, chastity, and self-reliance, into American political life and policy-making", and has been "greatly involved in Jewish conservative intellectual circles." Although she is often identified as a conservative, in Britain her most outspoken admirer is Gordon Brown, the former Prime Minister and head of the Labour Party, who frequently quotes her in his speeches and recommends her books. His introduction to the British edition of her Roads to Modernity, in 2008, opens: "I have long admired Gertrude Himmelfarb's historical work, in particular her love of the history of ideas, and her work has stayed with me ever since I was a history student at Edinburgh University."