His first commissions came from a large industrial brewery, the Diocese of Helsinki and Helsinki Municipality. His breakthrough came in 1876, when he was responsible for designing the buildings of a large industrial exhibition. Around the same time he received a prestigious commission from the industrialist Fredrik Wilhelm Grönqvist to build a large tenement house in a central Helsinki (1880), and subsequently got more and more commissions. These were often from the upper middle class, and many times concerned large buildings in central Helsinki (such as Hotel Kämp, 1886). To a degree it can be said that central Helsinki is characterised by the buildings of Höijer. He has been described as the foremost architect working in Neo-Renaissance style in Finland.
