Nam-gu once belonged to the Byeonhan confederacy during the Three Hans period, then, became part of Geumgwan Gaya when Byeonhan was being replaced by the Gaya confederacy. Later, when the Geumgwan-Gaya declined and Silla advanced, the area belonged to Daejeunghyeon in Silla during the Three Kingdoms period.
Nam-gu was incorporated into Dongnae-gun in the Unified Silla period. During the Goryeo Dynasty, it belonged to Dangnae. At the beginning of the Joseon Dynasty era, it was incorporated into Dongrae-jin, and then, it belonged to Dong-myeon and Namchon-myeon among seven myeons of Dongrae-bu, under King Yeongjo's reign.
Later, due to reorganization of administrative districts, it became a part of Seoha-myeon and Yongju-myeon. Then, Yongju-myeon in Dongrae-gun and a part of Nam-myeon were incorporated into Busan-bu, which was administered by Busan-jin branch on April 1st, 1936. The transition process since then is stated as follows.