After the death of Hossein Borujerdi in 1961, al-Milani was considered to be among Iran's leading grand Ayatollahs, along with Mohammad Kazem Shariatmadari and Ruhollah Khomeini.

[9] Al-Milani was born to a prominent religious family, that emigrated from Medina, and settled in Milan, West Azerbaijan, in the 14th century.

His father died when he was sixteen years old, and al-Milani was taken in by his uncle and to-be father-in-law Sheikh Abdallah Mamaqani.

[11] He was granted ijaza of ruwaya (narrating) from Sayyid Hasan al-Sadr, Abd al-Husayn Sharaf al-Din, Abbas al-Qomi and Agha Buzurq al-Tehrani.

He then decided to remain in Mashhad, at the request of its notable religious figures, who gathered and signed a petition for this.

Propagation of religious teachings were of utmost importance for al-Milani, and so he would send his students as missionaries to different areas, cities and villages across Iran.

[7] In Iran, he was active in the 1963 demonstrations in Qom, pioneering the clerical movement, and harshly criticised the Shah for his murderous actions.

In the same year, his passport was confiscated and he was ordered to leave Iran because he did not congratulate the Shah for his coronation, but the decision was not executed because of al-Milani's spiritual influence among people and his place among Shiite clergies and authorities.