He was the sixth son of Sir Randle Brereton, who was a member of Henry VII’s Court. William and his brothers entered the service of the King when they were young and he soon became popular. By 1521, William was made the Groom of the King’s Chamber. This was at an unusually young age, considering he was born around 1487. In 1524, he was promoted to the Groom of the Privy Chamber.

He was close to Henry VIII, much like Sir Henry Norris. It would have been a shock to the King to find out a close friend was having an affair with his wife, which is why it’s unlikely that Henry VIII had much input in the plot to remove the Boleyn faction. While Henry VIII wanted to remove Anne Boleyn, it is unlikely that he would have sent innocent men who were friends to die. He must have believed that Thomas Cromwell was telling the truth.

In 1529, William married the widow Elizabeth Savage; second cousin to the King and daughter of the 1st Earl of Worcester. This helped to cement his position in the Tudor Court and created a link to the King through family. After this marriage, Sir William Brereton gained an income of £10,000 per year and was the wealthiest man in the whole Court, behind the King of England.