Rabbi Pfeffer served as a rabbinical judge in a monetary court in Jerusalem, as well as as editor-in-chief of the Ner LaElef Resource Program and as chief rabbi of an international halakhic website (www.dinonline.org) and other rabbinical positions.
After growing up in London, he spent most of his years at the Mir Yeshiva, and did most of his rabbinical research under Rabbi Asher Weiss Shlita, from whom he received rabbinical ordination (including Yadin Yadin).
He has published books and articles on various topics in Halacha and thought (including research in Hebrew law at the Ministry of Justice), lectured at various forums in Israel and abroad and taught at several yeshivas in Israel (he currently teaches at the “Hedvot HaTorah” yeshiva). He headed a pre-academic school for ultra-Orthodox students, before serving time in the Israeli Supreme Court in Jerusalem, and is currently a senior director of the Tikva Israel Foundation, running programs (among other things) for ultra-Orthodox groups.