He was the son of Benoît de Cornouaille and the father of Hoël II, Duke of Brittany.
His family name, Canhiart, is understood to be derived from the old Breton Kann Yac'h[a] and was translated into the Latin texts of his era as Bellator fortis.
In part as a result of his rising power, he was attacked by Alan III but was able to push back the duke's army in 1031 in a battle near Locronan.
Around 1029, after a serious illness, Alain founded the Abbey of Sainte-Croix of Quimperlé with the assistance of his brother Orscand, the bishop.
As was the custom of the period, under the dowry arrangements Alain obtained five villages in Quistillic and half of the church of Cluthgual with the sepulchre and all appertaining rights.