A loyal vassal to Hugh Capet, he was able to reconstitute the union of the three counties of Amiens, Vexin and Valois in 965.
He maintained good relations with the Archbishop of Rouen, Hugh, Vexin being dependent on this diocese.
Walter recovered Mantes, while Meulan returned to Liutgarde's son Galéran II.
[2] Walter's first marriage was to a woman named Eva, the daughter of the Count of Dreux.
Secondly, he married around 950, Adèle, daughter of Fulk II the Good, Count of Anjou and Gerberga of the Rorgonids.