Zubanych became a company commander in the 15th Separate Mountain Battalion of the 128th Mechanized Brigade. On 6 December 2012, Zubanych was awarded the Medal For Military Service to Ukraine. He later became battalion chief of staff. He became commander of the battalion on 31 December 2013. From May 2014, he fought in the War in Donbass. Zubanych fought in battles in Novoannovku, Nyzhne Teple, Lugansk village, Makarove, and Shchastia. He served at mobile checkpoints, escorting supplies and convoys. Zubanych's positions were repeatedly shelled and attacked by separatists. While leading an assault group at the Lugansk Airport to cover the retreat of Ukrainian troops from an encirclement, Zubanych was wounded by shrapnel and also shot but continued to lead the unit and refused hospitalization. In November 2014, he fought in the Battle of Debaltseve. His battalion held Chornukhyne, Nikishynomu, Ridkodubi, Kamyantsi, and other points in the Debaltseve salient despite significant losses. The battalion was constantly under fire from BM-27 Uragans, BM-21 Grads, artillery, and mortars. On 23 March 2015, Zubanych was awarded the title Hero of Ukraine for his leadership.