The name Dunure is said to have come from the Celtic for "fort of the yew tree." The site dates from the late 13th century, the earliest charter for the lands is dated 1256.  The current remains of Dunure Castle date from the 15th and 16th centuries.

One tradition has it that the castle was built by the Danes, while another claims that the MacKinnons took the castle from Alexander III as a reward for their valor during the Battle of Largs.

The castle is the point of origin for Clan Kennedy, who once ruled over much of southwestern Scotland.  They were granted the rights to the land in 1357. Mary, Queen of Scots, is recorded as having visited Dunure Castle for three days during her third tour of the country in August 1563.

The castle is famous for the Roasting of the Commendator of Crossraguel in 1570. A dispute arose between the earl of Cassilis and the Commendator of Crossraguel Abbey, over the ownership and rental income of some lands.  The earl and his men caught the Commendator in Crossraguel Woods and tricked him into traveling to Dunure.  Once they arrived at the castle, the earl had the commendator's horse and weapons taken away.

For two days, the commendator was left to consider his fate. When he refused to hand over the lands, the earl resorted to more gruesome tactics: roasting and basting him over a brazier in the Black Vault. After undergoing two rounds of this torture, the commendator signed over the lands. The commendator survived this inumane treatment, and was rescued from Dunure Castle, but he never walked again.

In 1694, Dunure was described as "wholly ruined." Although it is not certain that this links to the Civil War, there is a local legend that states the castle was blown up at this time. A major collapse of the southeastern part of the keep could add credence to this tale.

Dunure Castle and its estate were purchased together with Dalquharran Castle by Sir Thomas Kennedy of Kirkhill in the late 17th century. There are said to be secret Ley tunnels that connect Dunure Castle to Greenan Castle further up the coast to the north.

Not far from the ruined castle you can find a more recent project, the Dunure Labyrinth.