He was the son of Qahtaba ibn Shabib al-Ta'i, who along with Abu Muslim led the Abbasid Revolution that toppled the Umayyad Caliphate. Along with his brother Humayd, Hasan was active in the Abbasid cause in Khurasan during the years before the Revolution, serving as a deputy "naqib". During the Revolution itself, together with his father he was one of the principal commanders in the campaign that brought the Abbasid armies from Khurasan into Iraq; he took part in the pursuit of Nasr ibn Sayyar and the victory at Nihavand, and despite his father's death in battle against the Umayyad governor Yazid ibn Umar al-Fazari, Hasan led the Khurasani army into Kufa.