He was the mayor of Novi Sad from 1993 to 1994 and the minister of the Serb diaspora in the Serbian government from 1998 to 2000, and has been elected to public office several times at the republican, provincial, and local levels.

He also removed the city's multilingual signs, increased the use of the Cyrillic script, and twinned Novi Sad with Ilioupoli in Greece.

Mirčić's ill-timed diplomatic visit to Ilioupoli at a time of economic hardship in Novi Sad was also described as a factor.

In September 1994, Mirčić disrupted the proceedings of the assembly to demand an emergency debate on the recent arrest of Radical Party leader Vojislav Šešelj.

[14] In the same month, the Wall Street Journal quoted Mirčić as saying at a Radical Party rally, "I want to create a country called Greater Serbia, with one parliament, one president, one army.

He added that the situation in Bosnia and Herzegovina was similar to that in Croatia and that Serbs in Macedonia were "trying to secure their basic rights and form their association.

Mirčić and Poplašen discussed cooperation between Serbia and the Republika Srpska and the issue of dual citizenship; a joint statement after the meeting blamed Dodik and his administration for blocking links between the communities.

In his speech to the assembled group, he said, "We have withstood and repelled most brutal physical attacks and have shown that we are capable to fight and defend ourselves.

"[25] Mirčić's term in office came to an end on 24 October 2000, shortly after the 2000 Yugoslavian general election and the resulting fall of Slobodan Milošević.

The SPS–JUL–SRS ministry fell from power after Milošević's defeat, and a transitional government was established in Serbia pending a new national assembly election.

[32] In November 2004, he and Venko Aleksandrov (the chair of Bulgaria's foreign policy, defence, and security committee) signed an accord for greater cooperation between their countries.

[37] In December 2004, he said that Albanian separatists in Kosovo were "waiting for helicopters and state-of-the-art small arms to be delivered to them from Croatia" and accused the groups in question of planning a campaign of ethnic cleansing against Serbs.

As in the republican election a year earlier, the Radicals emerged as the largest party in the assembly but fell short of a majority and ultimately served in opposition.

"[47] He also said, "by joining NATO, [Serbia] would be making a major concession to the advocates of independence for Kosmet [Kosovo and Metohija], because the alliance's strategy is not to interfere in internal conflicts in its member-nations.

[49] The Radicals suffered an unexpectedly poor result in this election, winning only twenty-four seats out of 120 while the For a European Vojvodina (ZEV) alliance led by the Democratic Party (DS) won an outright victory.

[50] Mirčić continued to lead the Radical Party group in the assembly and, from the opposition benches, accused the provincial government of pursuing a secessionist agenda.

[62] At another assembly meeting in early 2020, he took part in a media stunt by saying that Mihajlović was "known for spending state money on personal things" and attempting to give her a "gift" of pink underwear.

[63] More generally, Mirčić and other members of the Radical Party sought to portray Mihajlović as a stooge of the United States of America during her time in office.

He ran for Novi Sad's sixty-ninth constituency seat in the 2000 Serbian local elections and, like all SRS candidates in the city, was defeated.

[69][70][71] The party won the election and afterward formed a coalition government in the city; Mirčić did not return to a leadership role but instead supported the administration in the local assembly.

[72] He was given the second position on the party's list for in the 2008 local elections; the SRS won twenty-six seats, but he chose not to take a mandate for the term that followed.

[73][74][75] Mirčić appeared in the second position on the Radical Party's lists for Novi Sad in the 2012, 2016, and 2020 Serbian local elections and was re-elected each time.

He was blocked by protesters from entering the city assembly in August 2023 and tried to push his way in "by force"; he later said that he had never previously been restricted from exercising his duties as an elected official.