At the age of 17, he joined the professional association of locksmiths and the Social Democratic Party of Hungary (Magyarországi Szociáldemokrata Párt or MSZDP) in 1900, and later worked as the locksmiths' chief trustee at Manfréd Weiss Steel and Metal Works.
In the fall of 1918, he still took an anti-communist stance, but by March 1919 he had already become a supporter of unification and even joined the Party of Communists in Hungary (Hungarian: Kommunisták Magyarországi Pártja or KMP).
During the Hungarian Soviet Republic he was the People's Commissar for Social Production, alongside Jenő Varga, Antal Dovcsák, Gyula Hevesi, József Kelen and Mátyás Rákosi.
On July 31, 1919, he took part in the nighttime meeting led by Béla Kun, in which the hopeless situation of the Soviet Republic was discussed.
In 1920, following the collapse of the Hungarian Soviet Republic and the seizure of power by Admiral Horthy he was a defendant in the people's commissar trial.