The figure of God the Father is seated, right hand raised in what was almost certainly a gesture of benediction, though the fingers are long gone. Between his knees stands a cross bearing the carved figure of Christ, and above the arms of that cross a dove, representing the Holy Spirit, completes the Trinity. The head of the Father is missing entirely, the break running diagonally across the upper portion of the stone, and with it goes any certainty about the sculptor's original intentions at the top of the composition. What remains is still coherent enough to read as a theological statement in stone, a single carved object holding all three persons of the Trinity in deliberate spatial relationship to one another.

The sculpture's history is as incomplete as the object itself. Around 1812, an antiquarian named George Millar illustrated what appears to be a Trinity sculpture of this type, but he placed it at St Patrick's graveyard, roughly 900 metres to the south-east. That graveyard has been searched and nothing matching the description has been found there, which raises the possibility that the piece was moved at some point between Millar's record and the present day, though this remains unresolved. The style and material link it closely to a comparable limestone Trinity in Callan, also in County Kilkenny, which scholars have dated to the first half of the sixteenth century, suggesting a similar origin for this piece. Kilkenny was evidently producing or receiving such work with some regularity; a fifteenth-century alabaster Trinity sculpture, carved from the pale cream stone associated with English workshops of that period, has also been identified in the Black Abbey church of the Dominican friary, about 600 metres to the north of St Rioc's. The concentration of Trinity imagery across a relatively small area of the city speaks to a particular devotional fashion, and perhaps to the same network of patrons or craftsmen.