The church has a rectangular nave with a narrower apsidal chancel under a steep gabled roof, a plan largely unchanged since the Middle Ages. It belongs to a small group of Romanesque apse churches concentrated mainly in the western part of the county. A medieval west tower once stood here, but its upper section was demolished in 1818 after cracks appeared, with the lower part absorbed beneath the nave roof; the church bells now hang in a separate bell frame.
Inside, the Romanesque roof structure survives, and parts of the ceiling boarding are thought to be medieval. Cross vaults were added to the nave in the 15th century, though these were later removed and replaced with a wooden barrel vault when the tower was altered in 1818. A richly carved piscina, used for ritual hand-washing and disposing of baptismal water, remains on the apse wall near the altar, and a medieval limestone font base now forms the pedestal of the pulpit.
The most striking furnishing is the carved oak altar cabinet made in Lübeck in the second half of the 15th century, given to Kumla in the early 1700s by the neighbouring Svanshals parish, from whose church it originally came. It depicts the Coronation of Mary flanked by saints, with scenes from the life of Christ on its painted wings, and has been restored and regilded more than once. The medieval sacristy was substantially rebuilt in 1696.
The churchyard contains around 100 surviving gravestones, the oldest dating from 1892. A modest mechanical organ, built in 1863 by August Rosenborg of Vadstena with a case designed by Ludvig Hawerman, still stands in the church, its facade retaining much of its original gilding.