[4][5] Ansari has also been called the "first effective" model or Marja of the Shia[6] or "the first scholar universally recognized as supreme authority in matters of Shii law".

Returning from a pilgrimage to Mashhad, Khurasan, he encountered Ahmad Naraqi, an authority in fiqh, usul al-fiqh and irfan, and – although Ansari was already a mujtahid in his own right when he left Karbala – studied with him for a further four years.

After again traveling for a number of years, he returned to Najaf where he completed his studies under Kashf ul-Ghita and Muhammad Hasan Najafi (author of Jawahir ul-Kalam) and began teaching.

Despite this, Ansari lived humbly, generously provided stipends to his Islamic students with these funds, and this resulted in a confirmation of Najaf's standing as center of Shiah learning.

Morteza Ansari had devised a mode of distribution which included "junior mujtahids, low-ranking indigent ulama, Persian and Arab students, the custodians of the shrines, and the poor.

Of the former, his most important work is the Makasib, a detailed exposition of Islamic Commercial Law, which is still taught today in the Hawza and has yet to be surpassed.