Excavation has revealed that the site has been occupied since the 1st century BC and that it was in use during the years of the Roman occupation. The first historical mention of Bamburgh is in 547 when it appears as the seat of an Anglo-Saxon king, Ida. Ida's grandson Ethelfrith gave the castle to his wife Bebba. Over the years 'Bebbanburgh' became Bamburgh.

In 627 the newly crowned King Edward of Northumberland brought the Roman missionary Paulinus to preach Christianity in his lands around Bamburgh. Although Edward was killed by his Pagan enemies, his son Oswald carried on the work and summoned the monk Aidan from Iona to found a monastery on Lindisfarne (Holy Island) in 635. Northumbria became one of the great centres of learning and art, a golden age cut short in 993 by marauding Vikings, who left Bamburgh Castle in ruins.

The Normans built a new stone castle at Bamburgh, the great keep probably being completed by Henry II, and from its first siege in 1095 by William II until its last nearly four hundred years later it remained impregnable. During this time it remained a Royal stronghold against invading Scots and rebellious barons.

In the Wars of the Roses, Bamburgh was held by the Lancastrians and in 1464 it was captured by Richard Neville, Earl of Warwick, who pounded it to pieces with artillery before it surrendered. It was the first castle in England to succumb to cannon fire. Thereafter it gradually fell into disrepair and ruin with only the Norman Keep remaining intact.

The castle was eventually bequeathed for charitable purposes and a major restoration programme was started in the mid 18th century that continued in stages into the early 19th century. In 1894 the trustees sold the castle to the 1st Lord Armstrong, an inventor and industrialist, who started his own programme of reconstruction and modernisation. Since this time the castle has remained the home of the Armstrong family.