He was also one of the prominent heroes of the Battle of Mojkovac, where Montenegro helped the army of Serbia, its close ally, to retreat in face of Austro-Hungarian attacks.

Meanwhile, only several months after his arrival in Montenegro, Krsto Popović returned to Italy, where he served in the army of the Montenegrin government in exile, advancing to level of commander, and later to brigadier.

[3] King Alexander subsequently pardoned him and he returned to the Kingdom of Yugoslavia, receiving a pension and living in retirement until World War II broke out and Popović organized his collaboration militia, called the Lovćen Brigade.

This militia was under the control or influence of the fascist Italian occupation force, and it waged war against the Partisans and the Yugoslav Army in the Fatherland (Chetniks).

He was ambushed and killed in a shootout by OZNA agents Rako Mugoša [sr], Veljko Milatović and Šaro Brajović in 1947.