This article aimed to analyse the life and works of Mu'in al-Din Ḥasan Ibn Sayyid Giyaseddin as- Sijzī al-Chishti (d. 633/1236) as well as the effects of the Chishti Tariqa of which he was the founder, in the Indian Subcontinent. The importance and effects of Chishti Tariqa, the first and largest sect of India, in the spread of Islam and the construction of the basic structure of Islamic civilisation and culture are mentioned. The Chishti Tariqa emerged around 930 CE in Chishti, a small town near Herat, Afghanistan, and this tariqa got its name from its founder Mu'in al-Din Chishti. The essential condition of the Chishti Tariqa is a life in accordance with the Qur'an and Sunnah, that is, following the Sharia. According to Mu'in al-Din Chishti, Sufism without Sharia is superstitious. People who follow the path of Sufism without following the Shari'a cannot enjoy spiritual life in any way. Mu'in al-Din Chishti settled the Chishti order in Lahore and Ajmer in India in the middle of the 12th century. Mu'in al-Din Chishti is among the most well-known scholars, thinkers and sufis in the Indian subcontinent. In addition, Mu'in al-Din Chishti has a distinguished personality in social life. He saw the religious life as a service to the creatures and inculcated his followers to be in the social life and to serve the creatures. For this reason, he considered meeting the needs of the needy and feeding the hungry as a requirement of obedience to Allah and never neglected this. Due to his influence in India, Mu'in al-Din Chishti was given titles such as "Merciful to the Poor, Sun of India and Spiritual Sultan of India". He first stayed in Bukhara and Samarkand for a while for his education and then went to Baghdad. Mu'in al-Din Chishti also visited many important Islamic science centres of the period, such as Damascus, Mecca, Medina, Hamadan, Tabriz, Herat, Nishapur, Isfahan, Gorgan, Sabzevar, Balkh, and came to Lahore in India via Ghazni. Mu'in al-Din Chishti was also an influential Islamic scholar who devoted himself to the spread of Islam. Due to his invitation, many people accepted Islam in groups. The rulers of the period were disturbed due to the increasing number of Mu'in al-Din Chishti's influence circle and the people around him. The Hindu Raja, the king of the period, who thought his authority would be in danger, started to persecute Mu'in al-Din Chishti and his followers in various ways. However, Mu'in al-Din's influence on the people increased continuously despite all these problems. According to historical records, approximately nine million non-Muslims became Muslims in India under the influence of Mu'in al-Din Chishti. The study aimed to delineate Mu'in al-Din Chishti's life, scientific personality, works, influences and sect, lineage, mystical views, his travels for science, the Islamic scholars he met during his travels and learned knowledge, and his societal influences. Chishti's sufi doctrines were discussed through essential concepts in his works and the sect's method. In addition, the article also described the relations of Chishti with the rulers of his own time, the difficulties he encountered during his guidance of the people, and the reasons for these difficulties.