The purpose of this study is to verify the applicability of agency theory in the Korean corporate climate, which has undergone rapid changes since the foreign exchange crisis, and to derive a Korean corporate governance model that contributes to long-term value enhancement. To achieve this purpose, the author introduced corporate governance variables such as ownership concentration, institutional investor ownership, foreign investor ownership, and the proportion of outside directors, and analyzed how these variables individually or in combination affect balanced investment. One of the author's key assumptions is that corporate governance components exert greater effects when combined with one another than when acting individually. Empirical analysis of 399 listed firms revealed that foreign investor ownership and the proportion of outside directors had positive effects on balanced investment. Furthermore, the interaction terms between foreign investor ownership and the proportion of outside directors, as well as between foreign investor ownership and institutional investor ownership, also had positive effects on balanced investment. The results of this study suggest, first, that outside directors and foreign investors play a role in inducing firms to make investments that ensure long-term performance improvement, and second, that institutional investors, foreign investors, and outside directors combine to more effectively restrain managers' opportunistic behavior. These findings provide useful guidance for shareholders such as institutional and foreign investors who are focused on preventing managerial moral hazard, policymakers deliberating on policies related to corporate governance, civic organizations pursuing minority shareholder activism, and managers who are contemplating the direction of their investment behavior.