Originally a branch of Clan Donald, it is widely accepted that the Macalister clan was founded by Alastair Mor, son of Donald of the Isles.
The first mention of Alastair in records comes in 1253 when he is mentioned as witness to a charter granted by his brother Angus, Lord of the Isles, to the Abbey of Paisley.
Sometime in the 14th century, the descendants of Alastair appear to have settled in the county of Stirling but the chief family of the clan would then be granted lands in Kintyre in the far west of Scotland, where they would remain for 300 years.
Eventually, the Macalisters would sell the lands on Kintyre and move to the Scottish Lowlands at Kennox, in Ayrshire.
The current chief is William St John Somerville McAlester of Loup and Kennox.