William developed a reputation for the administration and supervision of royal building works during the reign of Edward III. By May 1356, he was clerk of the works for houses being built for the Crown at Henley on the Heath in Surrey and Easthampstead in Berkshire, and he was appointed surveyor of the long-running works to develop Windsor Castle in October 1356. He rapidly rose in royal service, and in July 1359 he was appointed chief keeper and surveyor of Windsor Castle, Leeds Castle, Dover Castle, and Hadleigh Castle, and many royal manors, including Sheen, Eltham and Langley, effectively in the office later called clerk of the king's works.