Askersund became a town in 1643, though its parish had to share worship with the surrounding countryside congregation until a wooden church was finished in 1651. That earlier church, a modest timber building near the old churchyard, was destroyed in a devastating fire that swept through the town on 6 June 1776. The disaster is said to have prompted sympathy from the royal court in Stockholm and the merchant community in Gothenburg, and by 1778 designs for a replacement were already in hand.
The new church was designed by Carl Fredrik Adelcrantz, one of the leading architects of the period, with plans approved by King Gustav III. It is regarded as a fine example of the neoclassical style that became fashionable in the later part of his career, complete with flanking wings. Learning from the fire, the builders chose brick rather than timber for the walls, giving the building far greater resistance to flame; the gently curved roof was originally clad in sheet metal. The church was consecrated in 1780.
Inside, light colours have long characterised the interior, which has never featured wall paintings. The ceiling takes the form of a wooden barrel vault finished with an elegant shadow-line moulding. The chancel is austere in design, with a large central niche where the altar is built directly against the wall; until a restoration in 2006, the altar rail and kneeler were also fixed to a lower platform within the altar area.
According to Wikipedia, the present altarpiece, altar rail and pulpit date from 1868 and were made by Johan Zacharias Blackstadius, while the chancel carpet is a modern work by Randi Fisher. This sits alongside an account describing an earlier altar painting of Christ on the Cross by a local painter named Falck, later replaced by a depiction of Christ on the Mount of Transfiguration, and crediting a local carpenter, Haldén, with the first pulpit. Visitors may notice differing traditions about the origins of these furnishings; both accounts agree that local craftsmen were involved, including an Askersund smith who made two decorative door locks, one of which can still be seen on the north entrance door.
The church's organ has been rebuilt several times, from an early eighteenth-century instrument through nineteenth-century and early twentieth-century organs by Swedish and German builders, to the current mechanical organ built in 1961 by Olof Hammarberg of Gothenburg.