Who was the first Mongol leader to convert to Islam?

Berke Khan was the first Mongol leader to convert to Islam. He ruled the Golden Horde, the Mongol successor state centered on the western steppe, from about 1257 until his death in 1266 or 1267.

Berke reportedly converted in Bukhara in 1252 after meeting Muslim travelers and learning about their faith. He was a grandson of Genghis Khan through Jochi, and his conversion made him an important early Muslim ruler within the Mongol imperial family. Islam had already spread among many peoples living under Mongol rule, but Berke was the first Mongol khan to make the faith central to his own rule.

His religious identity also shaped his foreign policy. Berke strongly opposed his cousin Hulagu Khan after Hulagu’s sack of Baghdad in 1258 and his campaigns against Muslim territories. Berke allied with the Mamluk sultanate of Egypt and fought the Ilkhanate, producing the first major open conflict between Mongol successor states.

Genghis Khan was associated with traditional Mongol religious practices, while Kublai Khan generally supported several religions. Hulagu was not the first Muslim Mongol leader either; Berke’s conversion came earlier and is the standard answer to this question.