Sir David Hunter Blair made some of his money in Jamaica and was joint-owner of Roselle Estate, St Thomas-in-the-East.

In late 2012, Sir Patrick David Hunter-Blair, 9th Baronet, sold Blairquhan to Ganten Scotland, a subsidiary of a Chinese company which bottles mineral water for distribution around the world.

The late James Hunter Blair (1926–2004), younger brother and heir presumptive of Sir Edward Hunter-Blair, 8th Baronet (1920–2006), was a noted horticulturalist and forester who spent most of his life restoring the castle and preserving the estate grounds, which include veteran trees and a walled garden.

To help offset operating costs, James Hunter Blair opened the 2,000-acre (800-hectare) estate as a venue for private functions such as weddings, corporate outings and filming.

Its interiors and grounds were also used as a substitute location for Balmoral Castle in the Oscar-winning 2006 film The Queen, starring Helen Mirren.