The globalization of the world economy has facilitated the transmission of risk across stock markets during financial crises. Although not directly financial in nature, macroeconomic uncertainties caused by health and geopolitical crises, such as the recent COVID-19 pandemic and the Russia-Ukraine and Israel-Hamas conflicts, have the potential to trigger shocks that may spill over into global financial markets. In this paper, we investigate the effect of macroeconomic shocks, specifically the COVID-19 pandemic and the Russia-Ukraine and Israel-Hamas wars, on the degree of stock market integration between South Korea and the United States. Previous studies present two opposing perspectives on how these recent shocks may affect global stock market integration. On the one hand, during periods of macroeconomic uncertainty, economic lockdowns or sanctions implemented to mitigate the transmission of shocks may reduce international trade volumes and capital flows, which in turn may weaken stock market linkages. On the other hand, another possibility is that stock market linkages may strengthen independently of the real economy. In the event of a global economic shock, emerging economies such as South Korea tend to implement macroeconomic policies similar to those of the United States to mitigate the impact on the real economy. This policy alignment has the potential to result in enhanced integration of stock markets, irrespective of whether these linkages directly reflect real economic conditions. Therefore, the extent to which stock market linkages are strengthened or weakened in response to macroeconomic shocks is an empirical question that merits attention. Furthermore, the degree of integration may vary depending on the nature of the shock, particularly when the shock manifests in different forms. In order to empirically investigate this issue, the DCC-MGARCH model is applied to the daily log return series of the KOSPI and S&P 500 stock market indices for the period from January 1, 2011 to January 31, 2024. We find that the shocks from the COVID-19 pandemic and geopolitical conflicts do not have uniform effects on stock market integration. In particular, during the COVID-19 pandemic crisis, the Korean stock market exhibited a greater degree of integration with the U.S. stock market than in previous years. However, the degree of stock market integration declined sharply during the Russia-Ukraine war. The results suggest that the simultaneous and multiple shutdowns in numerous countries worldwide during the COVID-19 pandemic, coupled with the implementation of quantitative easing policies to mitigate the impact of shocks, have contributed to an increase in stock market integration. In contrast, geopolitical risks, such as localized wars, appear to result in limited spillovers to stock markets. The results of our study provide valuable insights into the evolution of stock market integration during periods of uncertainty, emphasizing the importance of understanding the dynamic nature of stock market integration. Specifically, we suggest that during macroeconomic crises, both investors and policymakers should tailor their strategies according to the specific nature of the shock in order to diversify risk and optimize potential returns. While global stock market synchronization may potentially limit the efficacy of diversification, particularly during global crises, our findings underscore that the degree of integration between countries can exhibit considerable variability during periods of geopolitical risk. This variability presents opportunities for international diversification, which can assist in risk diversification and expected return enhancement. By taking into account the distinct characteristics of various shocks, policymakers and international investors can more effectively navigate macroeconomic uncertainty and implement more effective strategies for risk management. The significance of this study lies in its contribution of empirical evidence demonstrating that macroeconomic shocks exert differential effects on stock market integration, contingent on the nature of the shock. These findings bear significant ramifications for the formulation of government macroeconomic policy, the strategic portfolio composition of international investors, and the advancement of academic knowledge in this field. The study's analysis of the dynamic response of stock markets to diverse macroeconomic shocks, as influenced by their nature, provides a comprehensive framework for understanding these interactions.