The church is rectangular on plan. It was enlarged in 1677 and again in 1829, but much of the lower masonry courses may be of medieval date. Sections of a Romanesque string course survive on the exterior.

Early documents concerning the church no longer survive. The lands of the parish were primarily held by the Cistercian nunnery at Haddington, which was founded by the Countess Ada in the 1150s. It is not unlikely that the church was annexed to the nunnery about this time, as a 1298 tax roll lists the church amongst the possessions of the Haddington nuns.

Documentary evidence would seem to suggest a mid-12th century church. The surviving string course, with its string of diamond-shaped motifs, is found elsewhere in Scotland, an early example being St Margaret's Chapel in Edinburgh, which is unlikely to be before the 1120s. A mid-12th century date for Galvald seems likely, but not certain. A general date of either the 2nd or 3rd quarters of the 12th century is most credible.