[3] The cathedral was designed by Nicodemus Tessin the Elder (1615–1681) and is one of the foremost examples of classical baroque architecture that was a breakthrough in Sweden.

The design of Kalmar Cathedral reflects the complexities of modernisation, maintaining liturgical utility and tradition, and being mindful of the fortress-city requirements.

In 1831–1834, an external and internal restoration was carried out following a proposal by architect Jacob Wilhelm Gerss (1784-1844).

During 1910–1914 years of restoration took place according to drawings and job descriptions by city architect Josef Fredrik Olson (1870-1947).

Work included refurbishment of the church roof, stone restoration, facade staining.