During the rebellion of 1641, Alexander MacDonnell, the Earl of Antrim's brother, who was in charge of and resided in Glenarm, fought on the native Irish side. He raised several regiments who were garrisoned in Glenarm under the command of Alester McColl. In 1642 when an invading Scots army, under the command of General Robert Munro, was sent by parliament to deal with the rebels they burnt Glenarm, including the new castle. They captured both Alexander and the Earl and they were imprisoned in Carrickfergus Castle. When peace was brought about the Acts of Settlement and Explanation restored all the MacDonnells' land to them. They did not, however, rebuild the castle in Glenarm at this time, but moved to Dunluce Castle and later Ballymegarry.