The church consists of a nave and a straight-ended chancel, with a sacristy added to the east, probably in the 1400s, matching the chancel in width. A porch was built in the late medieval period but demolished in 1795 when the western entrance was created. Inside, the nave ceiling features a richly decorated star vault.
Among the fittings is a pulpit made in 1635, which was bought in 1695 from Björkviks kyrka rather than made for Halla itself. The altarpiece dates from 1705 and is the work of an unknown artist. A crucifix is flanked by symbols of the four evangelists — the angel, lion, ox and eagle — while the granite font was carved as recently as 1955, a reminder that the church's furnishings span many centuries.
The most memorable feature for visitors is likely to be the two painted figures above the triumphal arch, a man and a woman rendered in a caricature-like style with bold black outlines. An H marks the man and an M the woman, who is shown offering a drink from a cup. According to local legend, they represent Count Ture Bielke, owner of Åkerö slott, who was beheaded during the Linköping Bloodbath of 1600, and the woman said to have been given the unenviable task of sewing his head back on before burial — supposedly the wife of a chamber servant at Åkerö. This is a traditional identification rather than a documented fact, and visitors should treat it as legend.
The church has had at least two organs: an instrument with four stops built in 1848 by Anders Petter Halldén of Munktorp, later replaced by the current pneumatic organ, built in 1944 by E A Setterquist & Son Eftr. of Örebro.