Khorasani started his education in Mashhad and Sabzevar where he got familiar with philosophy and continued his education in Tehran where he learnt Logic and Hekmat. In 1861 he moved to (what is now) Iraq and in Najaf worked on complementary studies under Grand Ayatollah Mirza Hassan Shirazi who he succeeded as marja following Shirazi's death. He was a lecturer at Najaf seminary for years. His most famous work is The Sufficiency which ranks "only after Morteza Ansari's treatice on commercial law" among the legal works written by mullahs in the last two centuries. In The Sufficiency, Khorasani gathered the jurispurdential ideas such as `continuity` and "presented them in a yet more rigorous fashion as a unified theory of jurisprudence." Khorasani was not a sayyed but "owed his position almost purely to his intellectual accomplishments." 
Iran's Parliamentary Leader
Mohammad Kazem Khorasani was one of the main clerical supporters of the Iranian Constitutional Revolution. When Sheikh Fazlollah Noori declared journalists non-Muslims for their support of the new Constitutional Assembly, Khorasani retaliated by announcing that Sheikh Fazlollah was himself no longer a Muslim, leading to Fazlollah's execution. The reaction to Noori's execution in Najaf harmed Khorasani and other constitution supporters and led to a rivalry with Mohammed Kazem Yazdi.
Khorasani had a significant role in popularizing the modern concepts introduced by non religious intellectuals of his time. He emphasised "natural rights" of people and pushed the Iranian government and Shah to defend "natural rights".
- Iranian Constitutional Revolution
- Intellectual movements in Iran
- Mirza Malkom Khan
- Mirza Hussein Naini
- Mottahedeh, Roy, The Mantle of the Prophet : Religion and Politics in Iran, One World, Oxford, 1985, 2000
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