He was one of the most enthusiastic and steadfast disciples of the kabbalist Shneur Zalman of Liadi, rabbi of Liozna and Liadi, and studied under him until he had acquired a full knowledge of his mystic lore.
After Rabbi Shneur Zalman death in 1812, Aaron took up his residence as rabbi at Staroselye, and many flocked to him to have the Law explained in accordance with the teachings of his master. These formed a school known as the Hasidim of Staroselye. Rabbi Aaron was a descendant of Rabbi Isaiah Horowitz (Shaloh HaKadosh).
Rabbi Aaron's son, Haim Raphael HaLevi ben Aaron of Staroselye, was the second rebbe of Strashelye.