Ali was the son of Muhammad ibn Idris, whom he succeeded in March/April 836 at the age of nine.

[1] He proved an able ruler, who managed to stabilize and pacify the Idrisid realm after the troubled reign of his father.

[1] During his reign, Idrisid authority was strengthened and stretched from Basra to Tudgha.

[2] Some Idrisid troops reportedly also participated in the 846 Sack of Rome by Aghlabid raiders.

[2] Ali died in January 849 at Fes and was succeeded by his brother Yahya I.