Naomi Wiener Cohen was born in New York City to a Jewish American family and graduated from Hunter College in 1947. She attended the Seminary College of Jewish Studies, and earned a Ph.D. in history from Columbia University. In 1948, she married Gerson D. Cohen, a Jewish historian who later became chancellor of the Jewish Theological Seminary of America (JTS), with whom she had two children. She taught for 30 years at Hunter College, rising to full professor in 1973. She also served on the faculty of the Graduate Center of the City University of New York and of JTS. Following her husband's death and her retirement in 1996, she moved to Israel.
Her research focused on various aspects of American Jewish history, with a special area of interest being the German-Jewish community in the USA. Her books include A Dual Heritage: The Public Career of Oscar S. Straus (1969), Not Free to Desist: The American Jewish Committee, 1906–1966 (1972), Encounter with Emancipation: The German Jews in the United States, 1830–1914 (1984), and Jacob H. Schiff: A Study in American Jewish Leadership (1999). She also wrote about American Zionism in three books, including American Jews and the Zionist Idea (1975) and The Americanization of Zionism, 1897–1948 (2003).
She also made important contributions to understanding the complex interactions between American Jews and Christians, and on the separation of church and state in the USA. She received numerous awards for her work, including the American Jewish Committee's Akiba Award for Scholarship and Teaching; the Jewish Cultural Achievement Award in History; the National Federation for Jewish Culture Award in Historical Studies; and two National Jewish Book Awards.