In 1919, Janoušek led the Czech and Slovak section at the central committee of the Hungarian Communist Party. He was the only “chairman of the revolutionary committee” (predseda revolučného výboru) of the short-lived Slovak Soviet Republic, proclaimed in Prešov on 20 June 1919. The republic was created with military support from the Hungarian Soviet Republic. After the Hungarians were pushed out by troops of the First Czechoslovak Republic following the Hungarian–Czechoslovak War of 1918–1919, the Slovak Soviet Republic ceased to exist on 7 July 1919.
Janoušek died "in bed" of natural causes as reported by the historian V. Nálevka.[1] After cremation, his remains were buried at the Jan ŽižkaNational Monument at Vítkov. In 1990, his ashes were moved to Olšany Cemetery, together with those of about 20 other communist leaders which had also originally been placed in the Jan Žižka National Monument.[2]