The castle complex consists of a rectangular courtyard measuring approximately 40 metres long by 36.5 metres wide, enclosed by imposing walls that still reach heights of 9 metres. At each corner of this courtyard stand square towers, two storeys high with arched ceilings, containing tiny vaulted chambers barely 2 metres square. The main castle structure once stood detached to the north, and remnants of its grandeur remain visible, including three chimneys that tower 15 metres high, along with windows and fireplaces from former two-storey apartment ranges along the southern walls.

The castle's turbulent history reflects the broader conflicts of 16th and 17th century Ireland. Originally held by the Purcell family, Ballyculhane witnessed one of the more brutal episodes of the Desmond Rebellions in 1581. After David Óge Purcell successfully ambushed and nearly annihilated a raiding party from Adare garrison, English forces retaliated by storming the castle, resulting in the massacre of approximately 150 women and children. Despite this horrific event, the Purcells retained ownership until the Cromwellian conquest of the 1650s. The Civil Survey of 1654-56 recorded that Major General Patrick Purcell's estate included not just the castle and its bawn, but also three great houses, ten cottages, a mill site, and valuable salmon weirs on the nearby River Maigue.

The defensive capabilities of Ballyculhane were considerable for its time; the castle featured a wet moat that could be flooded from the River Maigue, adding an extra layer of protection to its already formidable walls. By 1703, an estate book described it as still being a large castle with strong walls, accompanied by a good garden and orchard, plus stables, suggesting it remained functional well after its military significance had waned. Today, ivy mantles the surviving walls, which remain about 3 metres thick and 6 metres high in places, offering visitors a haunting glimpse into both the architectural ambitions and violent realities of Anglo-Norman and Gaelic Ireland.