Rabbi Hillman was a descendant of his namesake Rabbi Shmuel Hillman (Helman), the Av Beth Din of Metz, who is mentioned in the introduction to the responsa Noda Biyhudah.
In addition, Rabbi Hillman was a direct sixth-generation descendant of the author of Knesses Yechezkel, who was the Av Beth Din of Altona, Hamburg and Wandsbek.