He is Sayyid Muhammad son of Sayyid Muhammad-Sadiq, son of Sayyid Muhammad Mehdi, son of Sayyid Isma'il, son of Sayyid Sadr ad-Din Muhammad, son of Sayyid Salih, son of Sayyid Muhammad, son of Sayyid Ibrahim Sharaf ad-Din; his genealogy reaches Imam Musa al-Kazim (as), one of the offspring of lmam Ali ibn Abu Talib (as) and Fatima al-Zahra (as), daughter of the Messenger of Allah (P).

His father, Sayyid Muhammad-Sadiq al-Sadr, is the cousin of Martyr Sayyid Muhammad Baqir al-Sadr who was executed together with his sister Bint al-Huda by Saddam Hussein al-Tikriti. Sayyid Muhammad al-Sadr was born in 1943 in Najaf al-Ashraf and started his studies at the hawza in 1954. In 1960, he joined the College of Fiqh (Islamic Juristic system) from which he graduated in 1964.