In 1974, Leff was appointed Rav of the
Young Israel of Greater Miami, located in North Miami Beach, Florida. In 1983, Leff and his family decided to make
aliyah to Israel, where he became the Rav and ''mora d'asra'' (rabbinic communal leader) of
Moshav Matityahu, a small
settlement now adjacent to
Modi'in Illit (Kiryat Sefer). At the time, the moshav was home to 11 families. which was geared to American-born students. and the Jewish Learning Exchange of London. He also teaches at Seminar Yerushalayim,
Neve Yerushalayim's Midreshet Tehillah, Michlala Women's College, and Bnot Torah; he formerly taught at the
EYAHT College for Jewish Women. He teaches "practical rabbinics" for the Ohr Lagolah Institute (based in
Ohr Somayach, Jerusalem). and the
Association for Jewish Outreach Programs. He is a rabbinic consultant for the Refuah Institute and Baruch Rofeh Cholim. ==Soccer game coverage==