He was the son of Frans Ferdinand Kanto from Jalasjärvi, who got a Swedish surname, Mattsson, when he joined the Finnish army. He changed the name in 1882. Meri means "sea" and refers to his voyage from Vaasa to Helsinki; Kanto refers to his origins from the estate Kanto in the Finnish-speaking area of Ostrobothnia.
He was notable for his variety of talents – he gave concerts all around Finland, performing on the piano and organ, conducting orchestras, and composing original music. Some of his most beloved compositions are Där björkarna susa, and the waltz Kesäillan valssi (Summernight's Waltz).
He died in Hausjärvi-Oitti.
His son Aarre Merikanto is one of the most notable Finnish composers.
- Romanssi, Op. 12
- Pohjan neiti (Maiden of the North) (1898)
- Nälkämaan laulu (The Song of the Hungry) (1911)
- various pieces for organ, including "Wedding Hymn"
He wrote vocal music in German, Swedish and Finnish. It includes
- Rote Blumen
- An den Fruhling/Keväälle
- Ström' leise / Oi, tyynny, sa virta
- Till Dig
- Ma Elän
- Rukous (Ave Maria)
- Pai Pai Paitaressu
- Piano Pieces 1: Suomalaisia Kansanlauluja 1. Vihko
- Piano Pieces 4: Suomalaisia Kansanlauluja 4. Vihko
- Piano Pieces 5: Suomalaisia Kansanlauluja 5. Vihko
- Free scores by Oskar Merikanto at the International Music Score Library Project
- Streaming audio at the Gustavus Adolphus College Archives
- Seppo Heikinheimo, Aarre Merikanto. Säveltäjäkohtalo itsenäisessä Suomessa. 1985
- Finnland Institut