İsa was one of the sons of Beyazid I, the Ottoman sultan. His mother was Devletşah Hatun, the daughter of Süleyman Şah of Germiyanids and Mutahhara Abide Hatun, daughter of Sultan Veled. İsa worked as a sanjak governor in Antalya and fought in the Battle of Ankara in 1402 with his father. The Ottoman army was defeated, Beyazid I was captured by Timurlane, and İsa escaped to west Anatolia.