 Sent to Egypt in 971, he became a leader of the Kutama Berbers and chief minister ("wāsiṭa") during the first year of the reign of the Fatimid Caliph al-Hakim bi-Amr Allah (r. 996–1021).Hasan was the son of Ammar ibn Ali al-Kalbi, a member of the Kalbid family, which had come into prominence through Ammar's brother al-Hasan ibn Ali al-Kalbi.Along with Ahmad, Ammar fought in the wars with the Byzantine Empire in Sicily and southern Italy, and drowned during an abortive expedition against Otranto in 958.