Karl Kilbom was born in 1885 in the Uppland region. His father was a smith who, when he tried to form a union, recieved threats from his employer and told Karl to stay out of politics. When he eventually moved away from his father (the mother passed away when he was young) he found a job as a sailor before eventually being drafted and serving at the ship HMS Svea in 1907. After his military service he moved to Göteborg, where he met big names in the left movement. Soon enough Kilbom started doing journalistic work for various political newspapers and became a big name in the far left movement of Sweden. In 1910, Kilbom moved to Halmstad to do work for the Social Democratic party there.
The Russian revolution
In 1915, Karl Kilbom had been made one of the main Swedish contacts with the Russian Bolsheviks and worked closely with Nikolai Bukharin who lived in Sweden during the Weltkrieg. In 1917 the party split in two and Kilbom joined its Left-leaning faction, which supported the revolution in Russia and was called the Swedish Social Democratic Left Party.
Kilbom traveled to Russia and after some difficulties at the border, they arrived in Petrograd and were greeted by Alexandra Kollontay. In Petrograd Karl Kilbom was taken to see a debate between Alexander Kerensky and Vladimir Lenin in front of a huge crowd of workers and soldiers. Kilbom did not understand what the speakers said, but afterwards Kollontay told him Lenin had spoken about the importance of making peace with Germany, while Kerensky had been speaking of continuing the war. The same evening, Kilbom had a chance to talk to Lenin briefly. They had met once before in Stockholm, and the Bolshevik leader now told him that a new revolution, in which the communists would take power, was imminent, and that he hoped the Swedish comrades would be prepared for the same.
Back in Sweden, Kilbom started working for the newly launched Left Party paper Politiken.