It is a quietly disorienting sight: Romanesque stonework and a functioning sports court sharing the same structure. Yet the west gable, which faces away from all of this, contains one of the more intricate Romanesque doorways in the county, its three arch orders carved with lateral and frontal chevron, the hood-moulding terminating in two beast-heads, and a tympanum bearing a badly eroded human face. Above the doorway apex sits a carved stone showing two figures in greeting, identified by Peter Harbison as St Moling and St Fiachra. The threshold itself incorporates a reused quernstone, worn flat by centuries of use.

The monastery at Ullard was reputedly founded by St Fiachra in the latter part of the sixth century, and the site retains a concentration of early medieval material: a high cross, a cross-slab, two bullaun stones (shallow bowl-shaped depressions cut into rock, used for grinding or ritual purposes), and a holy well, all within seventy metres of the church. The nave and chancel are built of roughly coursed granite rubble, and the chancel arch alone tells the story of several building phases: the original arch, nearly five metres high with decorated jambs and carved imposts, was later partially infilled and a smaller, cruder round arch inserted within it. Beneath the chancel floor lies a vaulted underground chamber, roughly five metres by two, its purpose somewhere between crypt and sacristy. By 1839 one of its wall recesses still held bones, and O'Leary recorded in 1948 that the Eustace family of Ballamurrough House had been buried in its floor. The chamber itself was a structural solution to the slope: without it, the chancel could not have sat level with the nave. The church's baptismal font was removed in 1814, carried 4.5 kilometres south to Graiguenamanagh abbey, where it remains.