After the uprising failed, Popović emigrated to Italy, but returned in June 1919 to start guerrilla warfare. He eventually laid down arms after the death of King Nikola in 1921 and he was eventually pardoned by King Alexander after proclaiming allegiance to him. He lived out his remaining years in Yugoslavia relatively peacefully until the Second World War when he formed the Lovćen Brigade. For this, he was labelled a collaborator by the new Communist government and in 1947 he was killed in an ambush by agents of the OZNA.