Marceli Handelsman was born on 8 July 1882, in Warsaw, to a family of distant Jewish ancestry. After graduating in law at the Russian-language Imperial Warsaw University, he moved to Berlin, where he began studies in the history department of Unter den Linden University. In 1906, however, he was dismissed from the school because of his involvement in socialist organizations. Afterwards Handelsman continued his studies at various European universities including Paris, Zürich (where he received his doctorate in 1908), Rapperswil, Vienna and finally London.
During World War I, in 1915, he returned to Warsaw and joined Warsaw University as a professor of modern history. He was also appointed a member of the Polish Academy of Learning. One of the most prominent historians of the age, between 1918 and 1939 he was also the editor-in-chief of the Historical Review and the head of a Commission for the Atlas of History of Polish Lands (1920–35). He was also a member of the Academy of Moral and Political Sciences in Paris and the London-based Royal Society.
After the outbreak of World War II Marceli Handelsman hid from the Germans because of his Jewish roots. Nevertheless, he took an active part in underground education in Poland during World War II and served as a professor in the underground Warsaw University. After 1942, under the noms de guerre "Maciej Romański" and "Maciej Targowski," he worked with the Bureau of Information and Propaganda of the Headquarters of the Home Army.
- Encyklopedia Polski.
- P. Węcowski, Marceli Handelsman (1882-1945), In: M. Handelsman, Historyka, oprac. P. Węcowski, Warszawa 2010, p. 343, 344; M. Wierzbicka, Marceli Handelsman, In: Słownik Historyków Polskich, ed. M. Prosińska-Jackl, Warszawa 1994, p. 175-177.