Mordechai Altshuler was born in interwar Poland in the city of Suwałki on October 25, 1932, to a traditional middle-class Jewish family.

[3] His grandfather Eliezer Mordechai Altshuler (1844–1921) was an activist in the proto-Zionist movement Hovevei Zion, who visited Ottoman Palestine to explore the possibility of acquiring land for Jewish settlements.

[5] After the end of the war in 1946, Mordechai returned to Poland with his family and settled in Wrocław, where he attended a Jewish school and participated in the Zionist youth movement Dror.

He wrote a number of works on demography,[5] Jewish identity, evacuation during the war, the specifics of the Holocaust in the USSR, etc.

[5] Since 1992, he has led a training program for teachers of higher educational institutions of the CIS on the history of Eastern European Jewry at the International Center for University Teaching of Jewish Civilization (Jerusalem).