After a short stay in Riga, which he spent writing a series of songs, he accepted a post as an organist at the Saint Nicholas Church[3] in Pärnu in 1903.

In that year he took the post of organist at the Church of Saint Anne at Liepāja, where he also conducted the choir of the local music society.

In the years 1927-1933 he lived in New York, where he worked as an organist, played concertos and gave music lessons.

In 2022, all organ works by Alfrēds Kalniņš were published both in a print edition and on a CD recording.

In 2004 it was replaced to the local school of music, which carries his name: Alfrēda Kalniņa Cēsu Mūzikas vidusskola.

In Viestura Park, also in Riga, there is a monument portraying eight Latvian composers, among them Alfrēds Kalniņš.

Kalniņš was a very prolific composer, who wrote hundreds of songs, both for solo voice with piano accompaniment and for choir.

In 1918 Kalniņš started working on his most famous piece of music, the opera Baņuta, which went into premiere in 1920 in Riga.

In the original version the principal person Baņuta and her lover Vižuts commit suicide; now the opera got a happy end.