At the outbreak of the World War I, Jambrišak was conscripted into armed forces of Austria-Hungary in Zagreb and deployed to Galicia at the Eastern Front.

[2] After the war, Jambrišak moved to Belgrade, in the newly established Kingdom of Serbs, Croats and Slovenes (subsequently renamed Yugoslavia).

[1] After the 1941 Axis forces Invasion of Yugoslavia, Jambrišak moved to Opatija where he stayed until September 1943 Italian surrender and the Armistice of Cassibile.

He then moved to the Yugoslav Partisan-held territory (together with Mandić) joining the Communist Party of Yugoslavia-led armed resistance against the Axis occupation during the World War II in Yugoslavia.

[1] Jambrišak was buried at the Vlašić Mountain, and a monument to him was erected at the site upon wish of the Yugoslav Partisans leader Josip Broz Tito.