The church was built between 1593 and 1619, during the turbulent decades following the Reformation, when tensions between Catholic and Protestant teaching still ran high in Sweden. It is sometimes seen as a symbol of that struggle. Curiously, Duke Karl is said to have taken Klara Church in Stockholm as his model, rather than any older Gothic cathedral.
The building's title of "domkyrka" (cathedral) is something of a historical curiosity: Mariestad was the seat of a superintendent, a church official ranking below a bishop, from 1580 to 1646, after which the office moved to Karlstad. A royal letter in 1696 formally stated that the church should no longer be considered a cathedral, yet the name has persisted.
Architecturally, the church is a late-Gothic hall church with a suggestion of transepts, pointed-arch windows, buttresses, and white ribbed vaults inside. Its three-sided choir became influential elsewhere in the diocese. The bare, unplastered stone facades and the tower's spire, which visitors see today, are not original to the building's early appearance: the church was originally rendered, and the exposed natural stone finish only dates from a restoration led by Folke Zettervall in 1905. The tower rises some 82.5 metres, making it the tallest building in Mariestad.
Inside, the Baroque altarpiece and pulpit, carved by Börje Löfman in 1701, are notable survivals from before later refurbishments. The pews and the free-standing limestone altar were introduced during a further restoration in 1958–1959 under Rolf Bergh, giving the interior much of its present appearance.
The church has had a succession of organs, reflecting Sweden's long organ-building tradition: a seventeenth-century instrument was destroyed by fire in 1693, and later organs from the eighteenth, nineteenth and twentieth centuries were rebuilt or replaced, most recently in 2011 by Tostareds Orgelfabrik, incorporating older pipework. A carillon of 20 bells, installed in the tower in 1972, is said to play hymn tunes at intervals during the day, alongside the cathedral's three older church bells.