The building's unusual round form dates from 1957, when it was built as a Konsum supermarket designed by Sune Flök. Its circular plan is said to reflect Italian influences, reportedly because the architect, married to an Italian woman, drew on round floor plans he had seen there. The structure has a cast concrete frame and a concrete tile roof.
As a shop, the building originally had no ordinary windows, since the wall space was needed for shelving; daylight instead entered through a roof lantern, a feature retained in the church today.
Conversion work began in autumn 1976, when the former shop hall was clad in yellow brick and the old goods entrance was glazed. The interior walls and ceiling were plastered white and the floor laid with ceramic tiles. The church was inaugurated on 4 September 1977, with Bertil Håkansson as architect for the conversion.
A freestanding wooden bell tower with a flat roof stands beside the church, housing a bell cast by the Bergholtz foundry in Sigtuna.
Västerslättskyrkan takes part in an ecumenical partnership known as "Tre kyrkor väst på stan" ("Three churches west of town"), together with Grisbackakyrkan and Hedlundakyrkan.