Pauls Kalniņš was born on 3 March 1872[2][3][4] (from other sources – 3 April[5]) at the Vilce Parish "Mazpečuļos" as a farmer's son.

After graduating from the local parish school, he studied at Liepāja Gymnasium,[5] where he met such later statesmen such as Miķelis Valters and Jānis Jansons-Brauns.

After returning to Latvia, he became a prominent member of the Social Democrats, a participant in the 1905 Russian Revolution, and was a collaborator in the editorial staff of Cīņa (now Neatkarīgā Rīta Avīze).

During World War II and the occupation of the Baltic states, Kalniņš was one of the founders of the Latvian Central Council,[8] the main political resistance movement, becoming its leader after the arrest of Konstantīns Čakste [lv] by the Gestapo.

[11] He was survived by his wife Klāra Kalniņa and son Brūno Kalniņš, who were also notable employees of the Social Democrats.