He was a son of al-Musayyab ibn Zuhayr, a participant of the Abbasid Revolution who later served as a provincial governor and security chief.
[1] In 792 he was appointed as governor (wali) of Egypt by the caliph Harun al-Rashid, as a replacement for the deceased Ibrahim ibn Salih.
During his governorship he is reported to have been engaged in hostilities with the people of the Hawf district, and to have received a request from the emir of Córdoba Hashim I for reinforcements in support of his raids against the Franks.
After remaining in office for a little under a year, he was dismissed and replaced with Ishaq ibn Sulayman al-Hashimi.
[2] In 795 Abdallah was again put in charge of affairs in Egypt, this time as resident deputy (khalifah) for the absentee governor Abd al-Malik ibn Salih, and he stayed in that position until Abd al-Malik's successor Ubaydallah ibn al-Mahdi arrived to replace him in the middle of that year.