The church as it now appears took shape in 1748, when it was remodelled into a cross-shaped plan, but the chancel and sacristy remain from the early 1300s. Traces of an even older building, thought to date from around the mid-13th century, have also been found beneath the present structure.
Inside the sacristy, wall paintings survive from the mid-15th century, attributed to the artist known as Mäster Amund, along with a medieval sacrament cabinet. A major renovation in 1933–1934 gave the church its current shingle cladding.
Hammarö has long been associated with pilgrimage. Travellers are said to have stopped here, often arriving by boat, before continuing north along the Klarälven river towards the shrine of Saint Olav at Nidaros Cathedral in Trondheim. Walking through the church today, visitors can trace this layered history in its carved wooden sculptures and painted decoration, even though the wall and ceiling paintings that once adorned the nave of the older church have since been lost.
Not everything is ancient: the stained-glass windows in the transepts date from 1934, a reminder that each generation has left its own mark on the building alongside what earlier centuries created.