Dating from as early as the 12th century, the castle is believed to have been constructed during the lordships of Uilleam and Domhnall, Earls of Mar. It has been posited that siting of Kildrummy Castle was influenced by the location of the Grampian Mounth trackway crossings, particularly the Elsick Mounth and Cryne Corse Mounth. Kildrummy Castle underwent siege numerous times in its history, first in defence of the family of Robert the Bruce in August-September 1306 (leading to the horrible deaths and executions of Nigel Bruce and many other brave Scots), and again in 1335 by David of Strathbogie. On this occasion Christina Bruce held off the attackers until her husband Sir Andrew Moray came to her rescue.
In 1374 the castle's heiress Isobel was seized and married by Alexander Stewart, who then laid claim to Kildrummy and the title of Earl of Mar. In 1435 it was taken over by James I, becoming a royal castle until being granted to Lord Elphinstone in 1507.
The castle passed from the Clan Elphinstone to the Clan Erskine before being abandoned in 1716 following the failure of the Jacobite rebellion.
Kildrummy Castle is "shield-shaped" in plan with a number of independent towers. The flat side of the castle overlooks a steep ravine; moreover, on the opposite side of the castle the walls come to a point, which was once defended by a massive twin-towered gatehouse. The castle also had a keep, called the Snow Tower, taller than the other towers, built in the French style, as at Bothwell Castle. Extensive earthworks protected the castle, including a dry moat and the ravine. Most of the castle foundations are now visible, along with most of its lower-storey walls. Archaeological excavations in 1925 uncovered decorative stone flooring and evidence of battles.
Today, the castle property is owned by Historic Scotland. A hotel (the Kildrummy Castle Hotel) has been built on the old estate, overlooking the ruins.