The castle was awarded to Robert Hardinge by King Henry II in 1153. Hardinge, who was the first of the Berkeleys, finished building the castle the same year. Berkeley Castle retains many of the defences that were installed to fend off attacks from the Welsh. These include arrow slits and huge fortified doors.

The castle has earned a degree of notoriety as the place of the imprisonment and ultimately the murder in 1387, of King Edward II. Edward had been a weak king who had made little secret of his homosexuality. Various commentators have reported that he was put to death by the insertion of a red hot iron bar into a place deemed fitting to his lifestyle, thus ending an insignificant reign and inspiring a name for the pop group "Eddie and the Hotrods". (This last part may not be true).

Elizabeth I too was a guest at Berkeley. The bowling green where she is said to have played is still on the grounds.

When it was first built; the area around the castle would have featured defensive waterways, diverted from the Severn nearby. The castle is now surrounded by magnificent Elizabethan Gardens and lawns. A striking lilly pond and a huge number of rare plants also adorn the grounds. The castle formerly had its own butcher to prepare meat from the medieval deer farm.

As well as the history surrounding the building itself, it is home to several items of historical interest. Sir Francis Drake’s cabin chest resides here. The Berkeley Gallery contains many works by English and Dutch Masters. A bedspread once owned by Queen Elizabeth I is on display. The archive at Berkeley Castle is home to more than 20000 documents, spanning the last 900 years of English history.