He is said to have helped Bakhtiyar Khalji during his Tibet campaign and converted to Islam under his influence.
Ali Mech is considered the first Muslim convert in present-day North Bengal.
[5] As a tribal chief in the foothills of the North of Bengal,[7] he aided Bakhtiyar Khilji in his failed invasion of Tibet in 1206 by acting as a guide.
[8] E. A. Gait mentions that he guided Bakhtyar Khalji march northwards along the right bank of the Karatoya river (present-day Bangladesh) for ten days, through a country inhabited by the Koch, Mech and Tharu (Terai) tribes.
Soon hundreds of Mech inhabitants converted to Islam due to growing oppression in the hands of Hindu lords and its caste, customs and traditions and as most of them were considered to be Yavanas or polluted outsiders by the Aryan hindus[9][10] and as they were lightly exposed to Brahmanic culture.