Walcher was a priest in Lotharingia from Liège and a secular clerk. He was invited by William I to fill the post of Bishop of Durham, and he was consecrated bishop in 1071 and probably enthroned on 3 April 1071. During the first part of his term as bishop, he was on friendly terms with Waltheof earl of Northumbria, so much so that Waltheof sat with the clergy when Walcher held synods. After Waltheof rebelled and lost his earldom, Walcher was allowed to buy the earldom of Northumbria. Walcher planned to introduce monks into his cathedral chapter, and was remembered as encouraging monasticism in his diocese. Particularly, he was known as the patron of Aldwine, who attempted to re-establish monasticism at Whitby. Eventually, the group settled at Durham under Walcher's successor William de St-Calais. The medieval chronicler Symeon of Durham stated that Walcher had begun construction of monastic buildings at Durham as part of his plan to introduce monks into Durham.