Natalia Aleksiun studied Polish and Jewish history at the Warsaw University, the Graduate School of Social Studies in Warsaw and Hebrew University in Jerusalem. She was a fellow of Foundation for Polish Science (Fundacja na Rzecz Nauki Polskiej), Batory Foundation, Fulbright, Lady Davis, YIVO Institute for Jewish Research in New York and the International Institute for Holocaust Research at Yad Vashem in Jerusalem. She received her doctorate from Warsaw University in 2001. Her dissertation appeared in print as Where to? The Zionist Movement in Poland , 1944-1950 (in Polish) in 2002. In 2010, she received her second PhD from New York University based on her dissertation entitled: "Ammunition in the Struggle for National Rights: Jewish Historians in Poland between the Two World Wars".

She published in Polin, Yad Vashem Studies, East European Jewish Affairs, Studies in Contemporary Jewry and German History. She is Associate Professor of Modern Jewish History at Touro College, Graduate School of Jewish Studies, New York. She was also Assistant Professor at the Institute of History, Polish Academy of Sciences. Currently, she is working on two book projects: on Jewish Historians in the Second Polish Republic and the so called cadaver affair at Medical Departments of Polish Universities in the 1920s and 1930s.