Due to his revolutionary activities, Mugoša was frequently arrested and persecuted, and after demonstrations in Peć in May 1940, he went underground.

[4] At the outbreak of World War II, Dušan Mugoša actively participated in organizing the uprising in Kosovo and Metohija.

[5] In October 1941, OK KPJ Kosmet representatives Boro Vukmirović, Dušan Mugoša, Pavle Jovićević and Ali Šukrija met with Albanian communist delegation made up by Koço Tashko, Xhevdet Doda and Elhami Nimani in Vitomirica (in Kosovo).

[7][8] He also worked on establishing the Communist Youth of Albania, and forming combat and sabotage groups to fight against fascist occupiers and their collaborators.

[5] On 25 May 1942, Mugoša began his trip crossing Montenegro, joining up with Todor Vojvodić and Spasoje Đaković in Andrijevica.