Wettenhovi-Aspa studied art in Denmark, where he was taught by artists such as Kristian Zahrtmann and Peder Severin Krøyer. In 1892, Wettenhovi-Aspa moved to Paris after he was awarded a grant. While living in Paris, Wettenhovi-Aspa took part in the Salon de la Rose + Croix in 1893 with Finnish sculptor Ville Vallgren and in Salon de Champ-de-Mars in 1894. In 1895, he was awarded a gold medal in an art exhibition in St. Etienne, France. Wettenhovi-Aspa had made his debut as a painter in 1891 in the Finnish Art Society's exhibition. He was a regular participant in Finnish art exhibitions in the late 19th and early 20th centuries, but he also arranged many exhibitions in Finland and other Nordic countries. Throughout his career, Wettenhovi-Aspa was seen in the Finnish press as a person seeking publicity and sensation whose art was at best controversial and amateurish. Wettenhovi-Aspa was a much contested figure in the Finnish art world, but at the same time, he was friends with many famous Finnish creative artists including composer Jean Sibelius and painter Akseli Gallén-Kallela.