Mačvan was born in Vukovar, into an ethnic Serb family. At three years of age (1992–93) he left Vukovar (which was struck by war) for Serbia with his family, living in Novi Sad with his mother for a period. At six years of age he returned briefly to Vukovar, where he started playing basketball for KK Vukovar. The family then moved to Bačka Palanka in northern Serbia.