On 2 February 2021 the National Security and Defense Council of Ukraine imposed sanctions on Kozak,[2] with the reason given for the sanctions being that according to the Security Service of Ukraine investigation, Kozak controlled a group of coal mines in the Donetsk and Luhansk regions not under government control whose profits contributed to the financing of terrorism,[3] as well as being implicated in the use of profits from the Samara-Western Direction oil product pipeline to fund the Donetsk People's Republic and the Luhansk People's Republic.

[11] In 2005 Kozak was a member of political party Russko-Ukrainskiy Soyuz that ran for parliament as part of the Natalia Vitrenko Bloc.

[11] As a nonpartisan candidate he took part in the 2012 Ukrainian parliamentary election in Ukraine's 122nd electoral district, around the city of Yavoriv in Lviv Oblast.

[18] At the end of 2018 Kozak official acquired several important Ukrainian television media such as NewsOne (from Yevhen Muraev)[19] and 112 Ukraine.

[25][26] In July 2019, employees of the ZIK TV channel, a number of newspapers, NGOs and institutions, a coalition of NGOs "Reanimation Package of Reforms" (more than 70 organizations), as well as public figures, journalists and public opinion leaders called on the state to take measures to prevent monopolization of media space by pro-Russian forces.

[2] Ukrainian President Volodymyr Zelensky stated that banning the channels had been a difficult decision and that Ukraine supported freedom of speech but not "propaganda financed by the aggressor country.

"[2] Russian Senator for United Russia Aleksey Pushkov claimed that "By shutting down opposition television channels, Zelensky acknowledged his inability to withstand political competition.

"[2] In a written statement the spokesperson of EU's Foreign Affairs High Representative Josep Borrell stated "while Ukraine's efforts to protect its territorial integrity and national security, as well as to defend itself from information manipulation are legitimate" it added that "any measures taken should be proportional to the aim".

"[33] Medvedchuk and Kozak were reported to keep funds in Belarusian banks controlled by business associates of President of Belarus Alexander Lukashenko, Aliaksei Aleksin and Mikalai Varabei.

[34] On 11 May 2021, Kozak and Medvedchuk were named as suspects for high treason and the illegal exploitation of natural resources in Ukraine's Russian-annexed Crimea.

[...] Kozak, who controls several news channels in Ukraine, supported the FSB’s plan to denigrate senior members of Ukrainian President Volodymyr Zelenskyy’s inner circle, falsely accusing them of mismanagement of the COVID-19 pandemic.