As team-centered organizational operations and structural arrangements have emerged as a new trend in management, the question of how to manage team projects to achieve better performance has attracted considerable interest from both academia and practitioners. This study identified five factors influencing team project performance—corporate culture, top management commitment (firm-level factors), team leader's leadership, coupling characteristics among team members, and team members' thinking patterns (team-level factors)—and examined their relationships with team project performance. In examining these relationships, this study classified team projects into regenerative and innovative types, with the criterion being the similarity or dissimilarity between projects previously undertaken by team members and the projects under investigation. According to the statistical analysis results, the relationships between project performance and influencing factors revealed both differences and similarities depending on the nature of the project (regenerative/innovative). Moreover, when comparing the Korean and Japanese firms in the sample, even among high-performing projects, relatively common characteristics were observed at the firm-level factors, while contrasting characteristics emerged at the team-level factors. Furthermore, comparing the results of this study with those of prior research, there are aspects where existing theories centered on Western contexts are applicable to East Asian firms, while there are also aspects that cannot be applied—a divergence that can be attributed to differences in national culture. Meanwhile, when analyzing the degree of applicability of existing theories in conjunction with the analytical results for Korean and Japanese firms, it is noteworthy that differences in management practices underlie the varying degrees of applicability of existing theories to the two countries' firms.