He became an assistant to the Finnish architect and designer Alvar Aalto while he was still a student. Before his studies were completed in 1937, he had participated in the design of a Helsinki department store called the Glass Palace. Early works emphasizing simple precise forms with smooth unbroken surfaces include the Teollisuuskeskus Hotel and offices in Helsinki (1952; in collaboration with Keijo Petäjä) and a hosiery factory for Kudeneule Ltd., at Hanko (1954–56). An increased freedom of form characterizes his four-tower apartment buildings in Tapiola (1959–60), which are rhomboid in plan; the cemetery chapel at Vitiala, near Tampere (1960–61), actually a group of buildings the most prominent of which is a large chapel with a parabolic shell roof; an apartment house in Helsinki-Munkkiniemi (1961–62), notable for balconies or verandas giving a view of the Gulf of Finland; and the Toronto (Canada) City Hall (1965), a combination of two gracefully curved, semicircular tower office buildings and a low-domed central structure.