Kranzler was born in Germany. His family fled the Nazis to the United States in 1937 when he was a child, and he was raised in New York. He studied for a BA (1953) and an MA (1958) at Brooklyn College, for an M.L.S. degree (1957) at Columbia University, and for his doctorate (1971) at Yeshiva University. He joined the faculty of Queensborough Community College of the City University of New York (CUNY) in 1969, and was a Professor there until his retirement.
He was a leading historian on the subject of aiding the Jews during the Holocaust, a field which his works founded. He was among the first to document the activities of Orthodox Jewish organizations, such as the Vaad Ha-hatzala and Agudath Israel. Historian Alex Grobman referred to Kranzler as "the pioneer of research on Orthodox Jewry during the war." He also researched and created awareness for the mid-1944 Swiss grassroots protests triggered by George Mantello publicizing Rabbi Michael Ber Weissmandl's translation of the Vrba-Wetzler report. Kranzler was convinced that these actions led to stopping of the transports from Hungary in mid-1944 and enabled the Raoul Wallenberg mission and other important initiatives in Budapest.
Kranzler was a contributor to the Goldberg Commission Report on the Role of American Jews During the Holocaust, and submitted two chapters, one on the Orthodox, called "Orthodox Ends, UnOrthodox Means" and another on the Jewish Labor Committee. He served as Scholar-in-Residence in numerous congregations, on college campuses, and centers, including the Spanish-Portuguese Synagogue (Rabbi Marc Angel) in Manhattan, and Kodima Synagogue, Springfield, Mass. (Rabbi Alex Weisfogel), Ohio State University Holocaust Center (Prof. Saul Friedman) and was given a fellowship at Yad Vashem.
Kranzler researched the aid of Jews during the Holocaust for about 35 years. He published ten books and many articles on the subject, and lectured on the subject in America, Israel, Europe and the Far East. He interviewed over a thousand people, including some of the major participants such as Hillel Kook also known as Peter Bergson, George Mantello, Rabbi Solomon Schonfeld and close family and associates of participants no longer alive, including Rabbi Michael Ber Weissmandl and Recha Sternbuch. He established one of the largest and unique research archives on the subject.
- The Man Who Stopped the Trains to Auschwitz: George Mantello, El Salvador, and Switzerland's Finest Hour, Foreword by Senator Joseph I. Lieberman, Syracuse University Press (March 2001), ISBN 978-0-8156-2873-6
- Holocaust Hero: The Untold Story of Solomon Schonfeld, an Orthodox British Rabbi, Ktav Publishing House (December 2003), ISBN 978-0-88125-730-4
- Thy Brothers' Blood: The Orthodox Jewish Response During the Holocaust, Artscroll (December 1987), ISBN 978-0-89906-858-9
- Japanese, Nazis & Jews: The Jewish refugee community of Shanghai,
- Heroine of Rescue: The Incredible Story of Recha Sternbuch Who Saved Thousands from the Holocaust
- Gutta, Memories of a Vanished World, ISBN 1-58330-779-6
- To Save a World (2 Volumes), C I S Communications, Incorporated (August 1991), ISBN 978-1-56062-089-1
NOTES: Some of the above are co-authored. Additional books not on the subject of are not shown.
- Goldberg Commission Report on American Jewry During the Holocaust
- Encyclopedia of the Holocaust
- The World Reaction to the Holocaust
- Yale Encyclopedia of the Holocaust
- New Dictionary of National Biography[clarification needed]
- "David Kranzler." Contemporary Authors Online. Detroit: Gale, 2001. Literature Resources from Gale. 30 Aug. 2010.
- Alex Grobman, Battling for Souls: The Vaad Hatzala Rescue Committee in Post-Holocaust Europe (KTAV, 2003), p. iii
- Dr. David Kranzler, Holocaust Teacher Resource Center, http://holocaust-trc.org/kranzler.htm
- "An Interview with David Kranzler," Sugihara: Conspiracy of Kindness, http://www.pbs.org/wgbh/sugihara/readings/kranzler.html
- Righteous Among the Nations
- Mark Klempner, author of The Heart Has Reasons: Holocaust Rescuers and Their Stories of Courage
- Zegota Council to Aid the Jews in occupied Poland
- List of people who helped Jews during the Holocaust