The church is built of local grey stone with sandstone dressings, and its long, tower-less nave with a narrower chancel and rounded apse gives it an unusually elongated, archaic silhouette. A dendrochronological study suggests construction in the 1150s, somewhat later than the traditional dating to the 1100s given in some accounts. The roof is shingled, and the windows are round-arched and irregularly placed, adding to its rustic medieval character.
Inside, the chancel retains its original barrel vault, and a small window in the apse opens onto a so-called 'heaven's stair' or Jacob's ladder: nine narrowing steps cut through the thick wall, once bricked up and only reopened during a 1930s restoration. The nave's mirror vaults date from the 1700s. For many years the interior was whitewashed, until restoration work in the mid-20th century uncovered fragmentary Romanesque wall paintings from the 1100s and 1200s on the triumphal arch, chancel walls and vaults — said to be among the most significant of their kind in the diocese.
According to local tradition, Bishop Bengt the Good gave the church its two bells and commissioned an especially costly reliquary shrine. The original medieval shrine, the Eriksbergsskrinet, was sold in 1875 and is now held at the Swedish History Museum in Stockholm; a copy remains in the church. The font, carved from local sandstone in the late 1100s, is thought to show direct English influence in its design, and has its own history of being sold and later returned to the parish.
The pulpit, signed and dated 1574, is said to be among the oldest surviving in Sweden, its four sides decorated with panelled fields in two tiers. The church has had three entrances into the nave over time: a stone porch to the west, a later brick or timber sacristy to the north added in the 1600s or 1700s, and a timber porch to the south from the late medieval period. Two lychgates of uncertain age stand in the surrounding churchyard wall, and a shingle-roofed bell tower was added in 1955, replacing an earlier one demolished in the 1880s.
When a new parish church was built in Eriksberg in 1885, this older building was abandoned and even used for a time as a grain store, before parishioners began holding services here again — reportedly because the new church proved difficult to heat in winter. The churchyard has not been used for burials since 1885, leaving it with an unusually untouched, meadow-like appearance dotted with old gravestones.