In 1924 he was arrested because of an illegal border pass, in 1929 he was accused of terrorism, then he was judged together with Vladko Maček.

He was promoted to the rank of General of the infantry and on 14 August 1941 he was named state secretary in the Ministry of Defence.

In August and in September 1944 he was commissioner of RAVSIGUR (Croatian: Ravnateljstvo sigurnosti, 'Directorate of Security') for the protection of the grand counties of Cetina, Usora, Soli, Vrhbosna, Hum and Dubrava.

In February 1944 he was promoted to the rank of lieutenant general, and in April 1945 he was promoted to colonel general, the highest rank in the Croatian Armed Forces on the authority of Ante Pavelić.

In May 1945, when Croatian forces retreated to Austria to surrender to British, he disappeared[8] The former Minister of the Interior of the First Slovak Republic Alexander Mach who was being held as a prisoner of war in a US camp in Natternberg near Deggendorf in 1945 recounts Vilko Begić’ remarks in his diaries, e. g. in the entry for 31 July 1945, which implies that Vilko Begić was still arrested in the camp in Natternberg at that time.