Lorberbaum was the great-grandson of the Chacham Tzvi, Rabbi Zvi Ashkenazi; he was therefore related to Rabbi Jacob Emden. According to one tradition, his father, Rabbi Yaakov Moshe, died before he was born, and his relative, Rabbi Yosef Teomim, the rabbi of Bursztyn, brought him up. This accounts for the common name that both father and son share. Another tradition states that before he was born, his father fell ill, and dreamed that he would recover in the merit of the son that would be born to him. In the merit of his future son, the father took his name-to-be. Yet another legend told, is that at his naming ceremony his father was preoccupied with his learning and thought they asked for his own name. He studied under Rabbi Meshulam Igra.