Built on a dolerite outcrop, the location was previously home to a fort of the indigenous Celtic Britons known as Din Guarie and may have been the capital of the kingdom of Bernicia, the realm of the Gododdin people, from the realm's foundation in c. 420 until 547, the year of the first written reference to the castle. In that year the citadel was captured by the Anglo-Saxon ruler Ida of Bernicia (Beornice) and became Ida's seat.
The castle was briefly retaken by the Britons from his son Hussa during the war of 590 before being retaken later the same year. In c. 600, Hussa's successor Æthelfrith passed it on to his wife Bebba, from whom the early name Bebbanburh was derived. Vikings destroyed the original fortification in 993.
The Normans built a new castle on the site, which forms the core of the present one. William II unsuccessfully besieged it in 1095 during a revolt supported by its owner, Robert de Mowbray, Earl of Northumbria. After Robert was captured, his wife continued the defence until coerced to surrender by the king's threat to blind her husband.
Bamburgh then became the property of the reigning English monarch. Henry II probably built the keep as it was complete by 1164. Following the Siege of Acre in 1191, and as a reward for his service, King Richard I appointed Sir John Forster the first Governor of Bamburgh Castle. Following the defeat of the Scots at the Battle of Neville's Cross in 1346, King David II was held prisoner at Bamburgh Castle.
During the civil wars at the end of King John's reign, the castle was under the control of Philip of Oldcoates. In 1464 during the Wars of the Roses, it became the first castle in England to be defeated by artillery, at the end of a nine-month siege by Richard Neville, 16th Earl of Warwick, the "Kingmaker", on behalf of the Yorkists.
The Forster family of Northumberland continued to provide the Crown with successive governors of the castle until the Crown granted ownership (or a lease according to some sources) of the church and the castle to another Sir John Forster in the mid 1500s, after the Dissolution of the Monasteries. The family retained ownership until Sir William Forster (d. 1700) was posthumously declared bankrupt, and his estates, including the castle, were sold to Lord Crew, Bishop of Durham (husband of his sister Dorothy) under an Act of Parliament to settle the debts in 1704.
Crewe placed the castle in the hands of a board of trustees chaired by Thomas Sharp, the Archdeacon of Northumberland. Following the death of Thomas Sharp, leadership of the board of trustees passed to John Sharp (Thomas Sharp's son) who refurbished the castle keep and court rooms and established a hospital on the site. In 1894, the castle was bought by the Victorian industrialist William Armstrong, who completed the restoration.
During the Second World War, pillboxes were established in the sand dunes to protect the castle and surrounding area from German invasion and, in 1944, a Royal Navy corvette was named HMS Bamborough Castle after the castle. The castle still remains in the ownership of the Armstrong family.
After the War, the castle became a Grade I Listed property. The description included this comment about the status of the building in 1952 and its history:
Castle, divided into apartments. C12; ruinous when acquired by Lord Crewe in 1704 and made habitable after his death by Dr. Sharpe ... Acquired by Lord Armstrong, who had extensive restoration and rebuilding of high quality by C.J. Ferguson, 1894-1904. Squared sandstone and ashlar.