Otto Olsson (1879-1964) was one of the greatest organ virtuosos of his time. He studied organ with Lagergren and composition with Dente at the Royal Swedish Academy of Music and then joined the faculty there, where he taught harmony and organ. He was also the organist at the Gustav Vasa church in Stockholm. He became a member of the Swedish Royal Academy of Music in 1915.
Olsson used his strong background in counterpoint combined with an affinity for French organ music to create his late Romantic style of composition. He also had an interest in earlier music and used the plainchant techniques of Gregorian chant in his Gregorianska melodier. He explored polytonality in his work, an advancement not found in other Swedish works of the time. In addition to many fine works for the organ, instrumental, and choral works, his best-known work is his setting of the Te Deum, a large piece for chorus, string orchestra, harp, and organ.
As a teacher, he influenced many Swedish church musicians, and he was important in the development of church music in Sweden, which had suffered a long period of decline, having served as a member of official committees that supervised the liturgy and hymnology. He also omposed Psalm settings for congregational use and wrote two instructional books, on the art of choral singing and psalm singing.