Zundelis Rozentalis was born on 28 May 1904 in Marijampolė, then part of the Russian Empire, to Abelis Rozentalis and Slava Soffa Aronaitė. In 1925, he finished the Rygiškių Jonas Gymnasium in Marijampolė, now part of independent Lithuania. That same year, he became a student of medicine in the medical faculty of the Vytautas Magnus University in Kaunas, but later switched to pharmacology. Financial difficulties forced Zundelis to suspend his studies. In 1938, he attempted to return to the university but was not admitted into his previous speciality. Then he changed his subject and in 1940 succeeded in becoming a student of chemistry at the Faculty of Mathematics and Natural Sciences of Vilnius University. However, several months later his studies were disrupted again, this time against his will: on 19 September 1941, Zundelis Rozentalis and many other Jewish students were expelled from the university on the basis of the Order of 17 September 1941 of the Higher Education Department of the Board of Education, which was subordinate to the Nazis. He returned to Marijampolė and was killed there in 1941.