This study constructed a process-based research model that divides the development process of international strategic alliances into pre-alliance formation, post-alliance formation, and continuous alliance-building stages, and then empirically analyzed the determinants of international strategic alliance performance of Korean firms using survey data from 339 firms engaged in international strategic alliances. The results of multiple regression analysis showed that in the pre-alliance formation stage, the partner characteristic variables of commitment and partner contribution were significant factors positively (+) affecting international strategic alliance performance. In the post-alliance formation stage, participation as a communication behavior variable was found to be a significant variable with a positive (+) effect. In the continuous alliance-building stage, the partner firm government's support policy was identified as an important factor determining the performance of international strategic alliances. Notably, the determinants of international strategic alliance performance and the relative influence of their variables were found to differ according to the performance variable throughout the entire alliance process. These analytical results suggest that in order for Korean firms to improve the performance of international strategic alliances, they need to establish alliance strategies appropriate to each stage throughout the entire alliance process, and in operating and managing alliances, they need to adopt different approaches depending on the performance variables that their firm considers important.