Sayyid 'Abd al-Husayn Sharaf al-Din al-Musawi was born in Kadhimiyya, Iraq, in the year 1290 A.H./1872 A.D. He left Lebanon to pursue his studies in Iraq at the age of 17.
Sayyid Sharaf al-Din attained the level of ‘ijtihad’ (independent reasoning on legal issues) at the age of 32 in the year 1322 A.H., returning to his home in Jabal 'Amil after having been away for fifteen years. He based himself in the city of Sur, and became known to his people in a short period of time. Later, the highest ranking religious authority in Lebanon, Sayyid 'Ali al-Amin, authorized him to issue ‘fatawa’ (juridical rulings).
In addition to his engagement in social work in Sur, and Jabal 'Amil, Sayyid Sharaf al-Din continued his efforts writing and publishing his works. Also, he struggled for the unity of the Muslims all the while. In the year 1327 A.H. he published al-Fusul al-Muhimah fi Ta'lif al-Ummah, a book which emphasized the necessity for the Muslims to unite. In this text, he addressed the disputes, and differences between the Shi'is, and the Sunnis.
In 1331 A.H., he had the opportunity to implement his views on Muslim unity. He visited Egypt and met Shaykh Salim al-Bishri, the head of al-Azhar University. The outcome of their discussions, and long deliberation was the book ‘al-Muraja'at’, which is highly recognized and circulated in the Muslim world, having been translated into twenty languages.
Al-Muraja'at is one of the best known books in Islamic studies due to its objective approach, depth, concise language, and the indisputable rationality of its arguments.
One of the steps he took to unite the Muslim umma was choosing the 12th of Rabi' al-Awal to celebrate the birthday of the Prophet Muhammad rather than 17th of Rabi' al-Awal. He deliberately chose this date because it was the one recognized by the Sunni Muslims [as opposed to Shi’is celeberating on 17th Rabi’ al-Awal], and he wished to bring all the Muslims, Shi'is and Sunnis, closer to each other. After observing this event in his mosque, Sayyid Sharaf al-Din al-Musawi went to the Sunni’s congregation to celebrate this occasion with them.
Sayyid Sharaf al-Din al-Musawi died in the year 1377 A.H or 1957 A.D.