[3] In 1905 Bar-Ilan joined the Mizrachi movement, representing it at the Seventh Zionist Congress, at which he voted against the Uganda Proposal to create a temporary Jewish homeland in British East Africa, as suggested by Great Britain.

[4] In 1911, he founded the Hebrew weekly newspaper Ha’Ivri in Berlin as a "non-party paper dedicated to all the affairs of Israel, faithful in its spirit to our religious tradition and to our national renaissance.

Published until 1921, the paper's contributors included such prominent writers as S. Y. Agnon, Joseph Opatoshu, Reuben Brainin, Eliezer Ben-Yehuda, and Yehuda Leib Maimon.

From 1920 through 1922, Bar-Ilan briefly served as acting president for what is now Yeshiva University during the temporary absence of its then-president, Bernard Revel.

[6] Along with Rabbi Shlomo Yosef Zevin, Bar-Ilan was the editor of the Talmudical Encyclopedia (Hebrew: אנציקלופדיה תלמודית), Volumes I (Jerusalem, 1946) and II (published posthumously in 1949).

He organized a committee of scholars to examine the legal problems of the new state in the light of Jewish law and founded an institute for the publication of a new complete edition of the Talmud.