Mariehamn’s parish was founded in 1905 when the town began to evolve. The foundation to build a church was established right after, but it took twenty years before the church was realised. Architect Lars Sonck, son of vicar Knut Sonck of the parish of Finström in Åland was contacted already in 1918 but the Civil War and political turbulence delayed the plans. The church was initially planned to be built on the Öhrebergsbacken, where Sonck ended up designing the town hall in the 1930s. The new plot for the church and parsonage in the middle of the Esplanade park was initiated by Sonck, Bertel Jung and Oscar Bomansson in the early 1920s. The architects debated that the plot in the middle of the esplanades would suit better for the size of the town’s church.

Sonck’s first sketches were made in 1924 and the construction started in 1926. St. George Church was consecrated on 11 December 1927. Bruno Tuukkanen was in charge of the decorations. The church represents Sonck’s stylistic evolvement from the Art Nouveau to Eclecticism. The building has references to Medieval churches and Art Nouveau. Later in the career, he developed his style mixing Art Nouveau, Nordic Classicism and even Functionalism. The church resembles St. Jacob chapel Lars Sonck designed to Paimio, near Turku in Western Finland in 1914. St. Jacob Chapel was built in 1929.

The parsonage is situated on the northern side of the plot. The red-brick building’s massing resembles massing of the church. Details are of Nordic Classicism. In between the church building and parsonage is a private courtyard which has a stone fence. The entrance to the courtyard is from the western side of the plot, next to the main entrance of the church.

Lars Sonck continued to work in Mariehamn for the rest of his life. He even designed the Maria Funerary Chapel (Mariakapellet) to the Mariehamn Cemetery. Architect Ruben Lindgren designed alterations for the altar of St. George church in 1959, based on Sonck’s alteration plans. Sonck had died in 1956.