His father was Mahmut Bey. He succeeded his father in 1312. Although he appointed his brother Yahşi as the governor of Konya, the Seljuk capital, Emir Coban, the Mongol commander, captured the city and Musa had to be contended with the former possessions of his beylik. However, he even lost Karaman, his capital city (ancient Larende) to his rebelling brother İbrahim, who was backed by the Mamluks of Egypt. According to Ibn Batuta, in 1332 he was ruling only in Ermenek. But in 1352, after a chaos period in the beylik, he was invited to Karaman, where he ruled till 1356.