Soon he and his family came back to the Kingdom of Montenegro, and as citizens of Cetinje, his father's native town, Filip finished elementary school.

By nationality a Montenegrin of peasant social background, he spent his childhood in very difficult circumstances, separated from his father, who returned to Cairo after participating as a volunteer in the First Balkan War.

A few months later, due to difficult material circumstances, he was employed in the administration of the magazine Misao, where he worked for several years and took exams at the Law Faculty.

Upon leaving the prison, he was sent to serve military service, when he passed two residual exams at the Faculty of Law, from 1938 until April 1941.

In February 1942, he became Secretary of the National Liberation Committee for the District of Cetinje, and two months later deputy political commissar of the Lovcen Partisan Detachment.

He remained in office until the formation of the Fourth Montenegrin Proletarian Brigade in which he assumed the post of Deputy Political Commissioner of the 5th Battalion.

He was appointed as instructor of the Central Committee of the CPY for party schools in units and on the terrain of Dalmatia and Bosnia.