For a period after the building fell out of religious use, the space served as a handball alley, with breaches cut through the chancel walls to allow access. It is an arresting collision of the sacred and the mundane, and it has left the fabric of the church in an unusual state: part ruin, part repurposed shell, with a chamfered two-light ogee-headed window still standing almost to full height in the east gable.

The church's origins lie with the medieval settlement of Earlstown and a charter of around 1200, in which Baldwin de Hamptonford, the lay patron, granted what he called "the chapel of Newtown, which is now a mother church" to the Priory of Kells. A dean named Robert was attached to Newtown in the early thirteenth century, and in the oldest surviving list of churches of Ossory the Rectory of Earlstown, as a parcel of Kells Priory, was valued at £8, with the vicariate at £4. In 1441, the church along with its chapels and glebe was confirmed to Kells Priory by royal letters. The parish was united with Kells in 1661, and it is thought the building went out of active use around that time. It appears on the Down Survey barony map of Shillelogher from 1655 to 1656, which places its abandonment in a fairly precise historical window. The structure itself tells a layered story: the architectural detailing was originally executed in sandstone, and then replaced in limestone during the later medieval period. Surviving sandstone fragments within the nave include door jamb pieces with a roll moulding and frontal fillet that date to the thirteenth century. At the east end of the south wall, the drainage channel of a former piscina, a small basin used for disposing of water used in liturgical rites, survives alongside fragmentary remains of an ambry, a wall cupboard for storing sacred vessels. Two opposing beam holes in the chancel end indicate there was once a rood beam, a horizontal timber that would have carried a crucifix separating the chancel from the nave.

A graveyard clean-up carried out between 1985 and 1987 uncovered a considerable number of medieval graveslabs and chest tomb fragments within the surrounding subrectangular graveyard, along with a cross and the pedestal of a font. The collection of stonework that has emerged from this site gives it a density of surviving medieval material that sits in quiet contrast to the plastered handball court occupying the nave end.