The church's core dates to the early twelfth century, with dendrochronological analysis of the chancel timbers pointing to construction in that period, likely on the site of an earlier wooden stave church. A local legend claims the earlier building was burned by Danish forces after the Battle of Lena in 1208, with the present church raised soon after by the parishioners; the sources do not confirm this story as verified history. The parish itself was originally called Lena, only becoming known as Kungslena from 1365.
The church's most recognisable feature is its trio of towers: a larger one above the centre of the nave and two smaller turrets over the gable ends. Tradition links these to a supposed visit by the regent Birger Jarl, his son the young king Valdemar, and King Håkon of Norway, who are said to have attended Easter mass here in 1258, with the towers built to commemorate the occasion. This remains a local legend rather than an established fact.
Built of limestone and rubble stone with whitewashed walls, the church consists of a nave, chancel, sacristy, and porches to the south and west. The building was extended in the fifteenth century, gaining an additional bay, vaulting, and its porch, while the distinctive roof turrets probably also date from this period. Larger windows were introduced in the seventeenth century, reportedly to relieve the gloom of the previously window-scarce interior, with further modernisation, including the current enclosed pews, carried out in the 1860s.
Among the oldest furnishings is a sandstone font from the twelfth century, attributed to the stonemason Master Harald, and an oak Madonna sculpture from the mid-thirteenth century on the nave's north wall, its paintwork renewed in the eighteenth century. A heavily reinforced medieval door with a wooden lock, leading to the sacristy, survives from the earlier church, its door handle reputedly shaped as a dragon slain by Saint George.on this later, sacristy-related door.
Fragments of medieval wall paintings from the 1480s, attributed to Master Amund, can still be glimpsed beneath later decoration, including scenes such as the flagellation of Christ and the martyrdom of Saint Erasmus. In 1749 Johan Risberg painted an extensive decorative scheme across the church, partly reusing Amund's earlier motifs, and further paintings were added in 1866. The sacristy also houses a medieval antependium, said to have been brought back from Bender by a local colonel who had followed Charles XII there after the Battle of Poltava, along with an altar cloth thought to be monastic needlework from Vadstena.
The church bells, cast in 1524, still hang in the freestanding bell tower built in 1679, which also houses a clock mechanism dating from 1716. The organ, built in 1989 by Robert Gustavsson's workshop in Härnösand, retains a silent façade inherited from an eighteenth-century instrument.