The castle’s origins trace back to the Dillon family, descendants of Henry de Lion who arrived in Ireland in 1185 at the behest of King John. The Dillons, who built their original house and chapel at Drumraney, went on to establish numerous castles and tower houses throughout the barony of Kilkenny West during the medieval period, though Portlick remains one of the few survivors. The imposing tower house, likely constructed around 1500, features a distinctive rectangular block with four projected corner towers that appear externally only as thin defensive loops, giving the structure its formidable character.

The castle’s complex architectural history reflects centuries of changing ownership and tastes. After the Dillons held the property until 1696, when Garret Dillon was declared attainted during the Williamite wars, the estate passed through several hands before being purchased by the Smyth family around 1703, who retained ownership well into the twentieth century. The Smyths added a plain Georgian wing around 1800; a seven bay, two storey extension that softened the medieval tower’s harsh defensive appearance. Following a devastating fire in 1861, Robert Ralph Smyth commissioned further Victorian improvements around 1865, including a castellated block that created the castle’s current entrance front: two towers connected by a low Georgian link, complete with stepped battlements and large mullioned windows in the fashionable Wyatt style.

The surrounding landscape holds equally fascinating historical layers. The 1838 Ordnance Survey map reveals a rich archaeological context, with ‘Church Park’ located 270 metres south containing the remains of an early Christian ecclesiastical complex, including a graveyard, possible church site, an early Christian cross slab, and even a motte and bailey castle. Another cross slab, recorded in 1976 as being built into an orchard wall 180 metres south of the castle but now lost, may have originated from this same ecclesiastical site. The Down Survey maps of 1654-57 provide a valuable snapshot of the castle in its purely defensive phase, depicting it as a tower house with a one and a half storey house attached to its eastern side, complete with tall chimney stacks rising above the roofline; a far cry from the hotel it serves as today.