Thomas Stanley, 1st Earl of Derby, had the castle built in 1490 to provide defence for his estates around Garstang.

[1] The land on which the castle was built is said to be a gift to Stanley from his stepson Henry Tudor for his assistance in defeating Richard III at the Battle of Bosworth.

[1] During the English Civil War the castle was garrisoned by James Stanley, 7th Earl of Derby in support of Charles I.

It was one of the last two Royalist strongholds in Lancashire to succumb following a bitter siege during 1644/45 by Oliver Cromwell's forces.

[1] The garrison at Greenhalgh Castle eventually surrendered in May 1645 provisional on their being granted safe conduct to return to their homes unharmed.