Following the outbreak of the war in Bosnia and Herzegovina, Poplašen left Sarajevo with his family to work for the newly-formed government of Republika Srpska in Pale. There he served as a member of the Advisory of Serb Democratic Party and also personally advised Radovan Karadžić. However, he left SDS in 1992 and founded the Serbian Radical Party of Republika Srpska. Subsequently, he worked as a commissioner for the government of Republika Srpska in Vogošća up to December 1992. He saw combat and was formally given the title of a Chetnik Vojvoda by Vojislav Šešelj.