First recorded in 1440 when it was seized by an O’Donnell son before being returned to the O’Boyle clan, the castle served as the O’Boyles’ principal residence for generations. The site saw considerable action during the Nine Years’ War; Red Hugh O’Donnell expelled English forces who had captured it in 1592, and by 1601 it was still recognised as the O’Boyle family’s chief house.

Following the Flight of the Earls, the lands of Ballyboyle were granted to Patrick Vans in 1610, marking the beginning of the plantation period. A year later, Paul Gore attempted to create something new from the old, constructing what was described as ‘a fair stone house’ from the castle’s ruins, though he was forced to surrender it to George Murrey. The property eventually passed to John Murrey, who would become Earl of Annandale. By 1622, visitors noted only ‘the ruinous castle of Ballyboyle’ with the walls of Gore’s house standing just seven feet high, and the 1654-6 Civil Survey recorded merely ‘ye old walls of ye Castle called Balliweill’.

Today, little remains of the original castle itself, though the site still holds traces of its defensive past. The ivy-covered ruins of a semicircular corner tower and sections of an adjoining wall, likely parts of a bawn or fortified enclosure, cling to the cliff edge. Archaeological surveys from the 1940s recorded four gun-loops at ground level and evidence of a mortared, corbelled vault that once roofed the tower, though portions have since collapsed into the sea. The foundations of the defensive wall can still be traced eastward along the cliff to a ruined gate-lodge, whilst about 2.7 metres of the northwest wall survives, standing roughly a metre high; silent testimony to a castle that once commanded this dramatic coastline.