Musa first appears as one of the "twelve naqibs" who prepared the Abbasid Revolution in Khurasan, and served as a commander when the revolt broke out, fighting in the Battle of the Zab.
Abdallah placed him as governor for the Jazira, where fought against pro-Umayyad rebels under Abu al-Ward.
[1] Caliph al-Saffah then appointed him as his sahib al-shurta, before sending him to Sind to overthrow the local governor, Mansur ibn Jumhur, who had seized the province during the turmoils of the previous years.
Defeated in battle, Mansur fled to the desert, where he died, and Musa succeeded him as governor.
[1] In 758 the new caliph, al-Mansur, appointed him as governor of Egypt, but his tenure there was brief, as he died within the same year (758/9).