South Korea's mortgage loan policy, which represents a regulatory policy for stabilizing the housing market, has changed significantly in accordance with changes in presidency and partisanship. Which partisan government's housing policy has been most effective in stabilizing the market? To answer this question, we discuss the different partisanships of Korea's conservative and progressive parties, their policy preferences, and the previous governments’ key housing policies. Thereafter, we concretize the research methodology and examine the housing volatility witnessed since 1987, using the Markov-switching regression. The results reveal that the market was highly unstable when the progressive government actively promoted regulation in favor of “governmentalist” partisanship. Moreover, the policy was mostly effective in lowering apartment prices in Seoul, which was the regulation's primary target all along. Based on these findings, we conclude with some policy implications of the study. Given that governmentalist partisanship heightens volatility in the housing market, housing market policies should be designed to hedge the negative externalities of partisanship.