His mature style combines the sensitivity to the dramatics of natural light of German Baroque churches, with compositional principles of Dutch De Stijl architecture of the 1920s, for instance in the way series of parallel, free-standing walls can define space yet deconstruct traditional notions of enclosure.
Leiviskä stated that his lighting fixtures are based on the principles developed by the Danish designer Poul Henningsen for his PH-lamps.
[5] Leiviskä also designed the JCDecaux bus and tram stop shelters used by the Helsinki City Transport company.
To qualify as architecture, buildings, together with their internal spaces and their details, must be an organic part of the environment, of its grand drama, of its movement and of its spatial sequences.
In 1997 Leiviskä followed Alvar Aalto and Reima Pietilä in becoming the architecture Member of the Academy of Finland - thus bestowing on him the title of Akateemikko (Academician).