Nemanov was born in Zhlobin in 1903. He studied in the Yeshivos of the fifth Lubavitcher Rebbe, Rabbi Sholom Dov Ber Schneersohn (the Rebbe Rashab). The sixth Lubavitcher Rebbe, Rabbi Yosef Yitzchok Schneersohn (the Rebbe Rayatz) appointed him the Rosh Yeshiva and Mashpia in various Yeshivos in cities of Russia, and he was appointed at the head of struggles against the Soviet regime, who incarcerated him several times and tortured him for spreading Torah and delivering classes in Chassidus. In 1947 he reached Paris and established a large Yeshiva in Brunoy.
He would pray at great length according to the custom of Chabad prayer. In Nemanov's thirties, the Rayatz testified that Nemanov had reached the level of Beinoni discussed in Tanya, one whose every thought, speech, and action is consistent with the Code of Jewish Law. Rabbi Menachem Mendel Schneerson sent many of his followers to Nemanov to receive guidance in their divine service.