This paper analyzes the political dynamics of capital account policy in South Korea. The first part is devoted to the historical evolution of capital account policy from the 1960s to the present day. It highlights the path of substantial financial opening that began in the early 1990s with two distinct waves of capital account liberalization before and after the Asian financial crisis of 1997-1998. The second part of the paper aims to detect the political origins of why capital account liberalization has not been complete and sustained. It locates them at the level of domestic informal institutions: first, the ideational legacy of the previous developmental state model - economic nationalism - that was predicated upon substantial barriers to international capital movements. Second, the political power of the export-oriented sector, namely of large conglomerates, that prefer exchange-rate stability and thus restrictions on capital inflows. This paper offers a heuristic argument based on a single case study which needs to be subjected to further empirical testing.