A minor when his father died, he was placed under the wardship of William Longespée, Earl of Salisbury, until he was of age. Knighted in 1229, he took part in King Henry III of England's expedition to Brittany and France in 1230. He was banned from attending tournaments at Blyth, Northampton and Cambridge between 1232 and 1234. When King Alexander III of Scotland was invited to attend the English court in 1235 and in 1237, Vesci escorted Alexander III. William took part in King Henry III's expedition to Gascony in 1242. In 1245, he was part in King Henry III's expedition to Wales. He founded the Carmelite priory of Hulne, Northumberland during his lifetime.