Later in World War II, Järv was a platoon leader in the 61st Infantry Regiment that consisted almost exclusively of Swedish-speaking Finns.

In September 1943 Järv was seriously wounded by a landmine and he spent the rest of the war at Saint Göran Hospital in Stockholm.

[2] After the war was over, Järv received a scholarship from Uppsala University and moved to Sweden where he spent the rest of his life.

Järv was the editor-in-chief in Swedish culture magazines Horisont, Radix and Fenix and was known as an eminent expert on Franz Kafka.

In 1952, Järv joined the Swedish anarcho-syndicalist union SAC and started writing articles in its newspaper Arbetaren.