ABSTRACT: In an altering global power architecture, South Korea has the national capacity to contribute to resolving transnational issues and has the potential to support a global common good. But in the discourse of South Korea’s role, the pivotal question has always been “how” to be a responsible middle power. Until now, South Korea has implemented its middle power in four different aspects: (1) Balancing Act in Northeast Asia; (2) ODA policy; (3) UN PKO; and (4) Global agenda setting. However, among the four, South Korea’s focus on balancing in Northeast Asia and ODA policy has been disproportionately concentrated in Asia due to national interests. This paper argues that in order to be a responsible middle power, South Korea should avert from a myopic Asian standpoint and concentrate more on global agenda setting through international institutions and the G20 platform. South Korea’s inherent structural constraints hamper a more proactive engagement in UN PKO. Therefore, global agenda setting is a more appropriate sphere to contribute to the world as a responsible middle power.