[2][3] He also served as the minister of finance and social welfare in the government of Montenegro and the cabinet of Zdravko Krivokapić from 2020 to 2022.

[5] As of 2025, he is the fourth youngest serving state leader in the world, after Ibrahim Traoré of Burkina Faso, Daniel Noboa of Ecuador and Kristrún Frostadóttir of Iceland.

[15] Spajić started his political career as a non-partisan politician and during the parliamentary elections in 2020 was a member of Zdravko Krivokapić's expert team.

[14] During the religious crisis, he participated in lobbying in the United States for interests of the Serbian Orthodox Church and the Serbs of Montenegro.

[8] During his term, Spajić and economy minister Jakov Milatović presented and implemented the controversial "Europe now" economic reform program.

[23] Instead of him, Milatović ran as PES candidate[24] and ended up defeating incumbent president Milo Đukanović in the run-off with 58.88% of the popular vote.

[33] On 30 August 2023, protests were held throughout Montenegro against Spajić and his plans to include the ethnic minority parties in the new government due to them being former coalition partners of the Democratic Party of Socialists (DPS) and for excluding the pro-Serbian coalition For the Future of Montenegro from the new government formation.

[36] He claimed that joining NATO was a "good move for Montenegro", but that he would be opposed to deploying Montenegrin soldiers to the Baltic countries.