Al-Hilli was born in Al Hillah, where he studied philosophy, theology and sharia (Islamic law). In 1305, Al-Hilli emigrated to Persia. He converted the Ilkhanate ruler Öljeitü from Sunni to Shi'a Islam, and as a result, Öljeitü proclaimed Shi'ite Islam as the state religion in Persia.
Al-Hilli wrote more than 500 works on theology and religion. Most famous is Treatise of the principle of Shi'ite Theology (Al-Bab al-Hadi 'Ashar). His works are standard references in the study of Shi'a Islam and are still used as textbooks in Iran.