In 1916 he was given ordination from David Horowitz, the Rabbi of Stanislaw, and the following year Weiss entered the University of Vienna.

In 1921 he completed a Ph.D. in History and Classical Philology, the topic of the dissertation being, "The Relationship of the Popes to the Jews During the Middle Ages".

Throughout this period Weiss continued his Talmudic studies under the guidance of Rabbi Aptowitzer, from whom he received an additional certificate of ordination in 1922.

In 1928 Weiss was invited to serve as Docent for Talmud at the Institute for Jewish Science in Warsaw, Poland.

Most notably, Weiss served as vice president of the Mizrachi Organization of Poland (1935–1940), and was appointed to the Jewish Committee (judenrat) of Warsaw.

This was a break from the previously held notion that the final editing of the Talmud occurred at the hands of Ravina and Rav Ashi, two late Amora'im.