Career
Margolis was ordained by Rabbi Jacob Barit and Rabbi Naphtali Judah Berlin. He taught and preached in Grodno (where his father-in-law Rabbi Nachum Grodno lived), before being invited to Vilna to assist Rabbi Eizele Charif publish his commentary on the Jerusalem Talmud. He later served as the head of the rabbinical courts in Dobrova, Mogilev Province, and Jasionowka.
In 1907, Margolis immigrated to the United States, settling in Boston, where he served as chief rabbi of seven local congregations.
In 1911, due to a dispute about kashrus he moved to New New York Margolis was involved in a fair amount of disputes in his lifetime due to his uncompromising religious views.