Nothing of the original monastery survives at ground level, and even the medieval church that preceded the current building has vanished entirely from sight, absorbed into the landscape of the graveyard that surrounds it.

The site's origins lie in the 7th century, when St. Fionan Lobhar, a figure associated with leprosy and healing in early Irish tradition, founded a monastery here. That community endured until 1178, when the Anglo-Normans burned both the monastery and the town below it. The church passed through several hands in the medieval period: it was confirmed to the Knights Hospitallers, a military religious order with extensive landholdings across medieval Europe, in 1212, with grants attributed to Philip of Worcester, who had served as Justiciar of Ireland in 1184, and to a Raymond de Carreu. By around 1300, under Prior Walter de Ewyas, a free chapel on the site was maintained with a daily chaplain, and the tithes were still being leased out as late as c. 1558, by Prior Massingberd. A sketch made in 1744 shows the medieval church already largely in ruins, though its central section remained roofed. That portion had been renovated for Anglican worship around 1724, but the entire structure was eventually replaced by the present building in 1807.

Visitors who look carefully around the graveyard will find physical traces of earlier phases of the site. Some window surrounds from the early 19th-century church, displaced when later alterations were made, lie scattered among the graves. In the south-east corner, close to the boundary wall, there is an early 17th-century chest tomb, a low rectangular box-like monument of a type common in Ireland during that period. Ardfinnan Castle and the medieval settlement lie roughly 350 metres to the south-south-west, visible from the churchyard, which gives some sense of how the ecclesiastical and defensive elements of this place once formed a single landscape.