Mikkola attended the Turku Cantor and Organ School in 1895 and studied at the Helsinki Music College in 1897–1899. In Paris, Mikkola studied singing and organ playing from 1900 to 1901 and made study trips to Germany in 1920 and 1929 and to Italy in 1929. Mikkola was the cantor of Turku Cathedral from 1901 to 1907 and the organist of St. Michael’s Church in Turku from 1908 to 1950. He also worked as an educator and in positions of trust in the music industry. From 1905 he had a piano and harmonium shop in Turku and Helsinki from 1912 to 1932. Mikkola worked as a music critic for Turku Sanomat from 1903 to 1912. He was awarded the title of Director musices in 1919.

Mikkola gave concerts in Turku and Helsinki, holding more than a hundred church concerts, among others, and worked as an orchestra conductor, organist and accompanist pianist.