After the war, he fled to the British Occupation Zone but was kidnapped by NKVD agents and executed in Moscow in 1946.

[1] During World War I, he served in the Imperial Russian Army in the Eastern Front.

He was awarded several Russian orders, including the Cross of St. George, and promoted to captain for his actions during the Christmas Battles in 1916.

[1] In August 1919, Kubiliūnas was mobilized to the Lithuanian Armed Forces and participated in the Lithuanian–Soviet War until December 1919.

[3] From August 1927 to July 1934, Kubiliūnas served as an officer of the Lithuanian General Staff.

[3] In 1934, for his support to the unsuccessful coup d'etat against President Antanas Smetona by followers of Augustinas Voldemaras, Kubiliūnas was sentenced to death by a military tribunal.

[5] During the occupation of Lithuania by Nazi Germany, he was the general counselor of the Confidence Council (Vertrauensrat), a collaborationist institution formed by the German administration of Generalbezirk Litauen in the Reichskommissariat Ostland, from late August 1941 till July 1944.

[7] He was transported to Moscow where he was interrogated and tried by the Military Collegium of the Supreme Court of the Soviet Union for treason under Article 58-1a of the Penal Code.