Early years (2003–16)

Damjanović joined the Radical Party in 2003.^[3] He appeared in the seventh position on the party's electoral list for the Belgrade municipality of Stari Grad in the 2008 Serbian local elections and received a local assembly mandate when the list won eleven seats.^[4][5][6] The alliance around the Democratic Party (DS) won a majority victory, and the Radicals served in opposition.

The Radicals experienced a serious split later in 2008, with several members joining the more moderate Serbian Progressive Party (SNS). Damjanović remained with the Radicals and led the party's assembly group in Stari Grad from 2008 to 2012.^[7]

In 2011, Damjanović took part in a protest against the extradition of Ratko Mladić to the International Criminal Tribunal for the Former Yugoslavia (ICTY). He was quoted as saying, "[His arrest] is an act of treason by the regime. It proved that this country is not free. He's [i.e., Mladić is] a hero."^[8]

In the 2012 local elections, Damjanović received the twelfth position on the Radical Party's city list in Belgrade and the second position on its municipal list in Stari Grad.^[9] Weakened by the split four years earlier, the party fell below the electoral threshold for representation at both levels. Damjanović later appeared in the seventeenth position on the SRS list for the Belgrade assembly in the 2014 Belgrade City Assembly election^[10] The party again fell below the threshold.

In 2015, Damjanović joined with SRS leader Vojislav Šešelj to burn a Croatian flag in front of the High Court in Belgrade. In a subsequent television interview, he said that the Radical Party would always support "burning the flag of the state that occupied the Serbian Krajina."^[11]

Parliamentarian (2016–20)

Damjanović appeared in the ninety-second position on the SRS's list in the 2012 Serbian parliamentary election and the thirty-first position in the 2014 parliamentary election.^[12][13] As at the city level in Belgrade, the party fell below the electoral threshold on both occasions.

He was promoted to the eighth position on the party's list in the 2016 parliamentary election and was elected when the list won twenty-two seats.^[14] The Progressives won the election, and the Radicals served in opposition. During his parliamentary term, Damjanović was a member of the committee on Kosovo-Metohija and the committee on finance, state budget, and control of public spending, a deputy member of the European integration committee and the European Union–Serbia stabilization and association committee, and a member of the parliamentary friendship groups for Belarus, China, Russia, and Venezuela.^[15]

Damjanović was the leader of the Radical Party's city organization in Belgrade in this period. In April 2016, he announced that the Radicals would join a coalition government in Stari Grad led by their traditional ideological rivals in the Democratic Party (DS).^[16] This was later contradicted by the DS, which contended that no formal agreement had been reached.^[17]

Damjanović announced in March 2017 that the Radical Party would send an international parliamentary delegation to Crimea to mark the three-year anniversary of the area's de facto joining of the Russian Federation.^[18]

While serving as a parliamentarian, Damjanović was the Radical Party's nominee for mayor of Belgrade in the 2018 Belgrade City Assembly election and appeared in the second position on the party's electoral list for the city, behind Šešelj.^{[19][lower-alpha 1]} During the campaign, he called for the abolition of "anti-Serbian non-governmental organizations" and proposed building a monument to former Serbian president Slobodan Milošević.^[20] The party fell below the threshold for assembly representation. After the election, he said, "We will not give up our ideology. We will not change our program. [...] The people will decide if and when they will trust the SRS, our program and our ideology."^[21]

Damjanović appeared in the sixth position on the Radical Party's list in the 2020 parliamentary election and was not re-elected when the list fell below the electoral threshold.^[22]

Parliamentary Assembly of the Council of Europe (2016–21)

Damjanović was a substitute member of Serbia's delegation to the Parliamentary Assembly of the Council of Europe (PACE) from 2016 to 2021. For his entire term, he was an alternate delegate on the committee on social affairs, health, and sustainable development. He was a member of the Free Democrats Group from April 2019 until the group's dissolution two months later; apart from this, he did not serve with any assembly grouping.^[23]

Since 2020

Damjanović again appeared in the sixth position on the Radical Party's list in the 2022 parliamentary election and was promoted to the fifth position in 2023.^[24][25] The list fell below the electoral threshold on both occasions.

In May 2022, Vojislav Šešelj received a summons to appear before the International Residual Mechanism for Criminal Tribunals (the successor body to the ICTY) to respond to charges concerning the publication of classified information and the names of protected witnesses. The summons also included the names of seven current and former Radical Party officials, including Damjanović.^[26] An indictment was later filed against Šešelj, Damjanović, and three other Radical Party officials on 11 August 2023. In late February 2024, the presiding justice ruled that the case should be transferred to Serbia.^[27] Damjanović has said that he was included in the indictment simply by virtue of having made Šešelj's books concerning the ICTY available to the public.^[28]

In March 2024, Damjanović led a Radical Party delegation to a vigil at the grave of Slobodan Milošević.^[29]