Some make him a descendant of Gōdarz and of the vizier Bozorgmehr and call him Ebrāhīm; some name him Behzādān, son of Vendād Hormoz; and others relate him to the Abbasids or to the Alids.

[8] When Abu Muslim arrived in Khurasan, the province was in turmoil due to the impact of the ongoing Umayyad civil war of the Third Fitna, which had re-ignited the feud between the Yaman and Qays tribal groups: the numerous Yamani element in the province opposed the longtime governor, Nasr ibn Sayyar, and sought to replace him with their champion, Juday al-Kirmani.

Al-Kirmani led an uprising against Ibn Sayyar, and drove him from the provincial capital, Merv, in late 746, with the governor fleeing to the Qaysi stronghold of Nishapur.

[9][10][11] He took Merv in December 747 (or January 748), defeating the Umayyad governor Nasr ibn Sayyar, as well as Shayban al-Khariji, a Kharijite aspirant to the caliphate.

He became the de facto governor of Khurasan, and gained fame as a general in the late 740s in defeating the rebellion of Bihafarid, the leader of a syncretic Persian sect that was Mazdaist.

[4] His heroic role in the revolution and military skill, along with his conciliatory politics toward Shia, Sunnis, Zoroastrians, Jews, and Christians, made him extremely popular among the people.

Although it appears that Abu al-'Abbas al-Saffah trusted him in general, he was wary of his power, limiting his entourage to 500 men upon his arrival to Iraq on his way to Hajj in 754.

Relations deteriorated quickly when al-Mansur sent his chamberlain Abu-al Khasib to inventory the spoils of war, and then appointed Abu Muslim governor of Syria and Egypt, outside his powerbase.

Abu Muslim's eventual downfall and execution on charges of heresy have contributed to doubts cast on the sincerity of his Islamic faith.

I shall not turn back until I have destroyed the Kaaba, for this has been [wrongly] substituted for the sun; we shall make the sun our qibla as it was in olden time"[17]Despite his assistance in crushing Behafarid's heresy and the possibility of his own Zoroastrian sympathies, Abu Muslim has not been remembered favourably by the Zoroastrian Orthodoxy in the Middle Persian tradition, as both the Zand-i Wahman yasn and Zaratosht-nama censure Abu Muslim.

[13] He became a legendary figure for many in Persia, and several Persian heretics started revolts claiming he had not died and would return;[13] the latter included his own propagandist Ishaq al-Turk, the Zoroastrian cleric Sunpadh in Nishapur, the Abu Muslimiyya subsect of the Kaysanites Shia, and al-Muqanna in Khurasan.

[citation needed] There are different variations of legends about Abu Muslim and forms of his worship in Central Asia, Iran and Afghanistan.