Aino Maria Mandelin was born on 25 January 1894 in Helsinki to a working-class family of 13 children. Her parents changed the family name Mandelin to Marsio in 1906, as a part of the finnicisation movement. Aino Marsio took her matriculation exam from Helsinki Finnish Girl’s school in 1913. In the same year, she enrolled at the Institute of Technology to study architecture. By the time, 13 women had already graduated as architects in Finland. Marsio received the diploma of architecture in 1920.

Marsio made her first study trip to Italy in 1921 with her friends and colleagues Aili-Salli Ahti and Elli Ruuth. Two years later, in 1923 she moved from Helsinki to Jyväskylä to work at Gunnar A. Wahlroos’ office. In 1924 she married Jyväskylä based young architect, Alvar Aalto and started to work at his office. After marriage, she used the name Aino Marsio-Aalto, but as a designer and architect, she also used the shorter version of her name, Aino Aalto. She specialised into interior and furniture design in their collaborative projects. Their daughter, Johanna ”Hanni” Aalto was born in 1925.

In 1927 Aino and Alvar won their first architectural competitions, Southwest Finland Agricultural Cooperative Building in Turku and Viipuri Library in Southern Karelia. In 1928 Marsio-Aalto gave birth to a son, Hamilkar Aalto. During the development of the Southwest Finland Agricultural Cooperative Building in 1929, the Aalto family moved to Turku. In 1929 the Aaltos won the architectural competition of Paimio Sanatorium. The sanatorium, completed in 1932, was the international breakthrough for the architect couple.

The Aaltos moved to Helsinki in 1933. In 1936 the Aalto House, a total work of art, was completed. That same year they founded Artek furniture company together with Maire Gullichsen and Nils-Gustav Hahl. Aino Marsio-Aalto was appointed as the Design Director of Artek. The Aalto office’s one of the most well-known projects, Villa Mairea, a villa for Maire Gullichsen and her family in Western Finland, was completed in 1939. The Aalto’s developed the ideas used in their own home in the design of the Villa Mairea. Marsio-Aalto became the Managing Director of Artek in 1941, after Nils-Gustaf Hahl had been killed in the Continuation War.

The association of female architects in Finland – Architecta – was founded by Marsio-Aalto, together with her friends and colleagues in 1942.

Aino Marsio-Aalto died at the age of 54, on 13 January 1949 in Helsinki. She is buried in Hietaniemi cemetery in Helsinki.