As evidenced by his nisba, Ammar hailed from the Arab Banu Kalb tribe, and belonged to an aristocratic family established in Ifriqiya since the Muslim conquest of the Maghreb.
Along with his brother Hasan, Ammar belonged to the close circle around Jawdhar, the powerful chamberlain and chief minister of Caliph al-Mansur bi-Nasr Allah.
The local Byzantine commander, Marianos Argyros, visited the caliphal court and arranged for truce, but it was soon broken and warfare resumed.
Another effort by Argyros to renew the truce in autumn failed, and in the next year, Ammar and Hasan defeated his forces in Sicily; but soon after, as the Fatimid fleet was returning from Calabria to Sicily, it was again wrecked in a storm off Palermo, in which Ammar perished (on 24 September 958, according to the Cambridge Chronicle; al-Maqrizi places these events two years earlier).
[3][4] Ammar's son Hasan also served against the Byzantines in Sicily and Italy before going to newly conquered Egypt,[5][6] where he rose to become chief minister under Caliph al-Hakim bi-Amr Allah in 996–997, before being overthrown and executed by Bajarwan.