Purpose: This study investigates the motivations, contributions, and challenges faced by international researchers employed at Japanese companies. It utilizes Tomlinson's Graduate Capital Model to gain insight into their experiences. Design/Approach/Methods: This study employs Tomlinson's Graduate Capital Model as an analytical framework to analyze data from semi-structured interviews with 15 international researchers, focusing on their experiences and perspectives. Findings: The study indicates that international researchers' motivations to work in Japanese companies include professional advancement, the research environment, academic opportunities, economic factors, and cultural elements. Language proficiency in Japanese and English significantly influences career choice and mobility. The post-COVID era impacts their mobility, with funding availability, institutional support, and policy changes playing critical roles. In addition, this study highlights the need for holistic support, multilingualism, and multicultural integration among Japanese companies to enhance their competitiveness in the global talent market. Originality/Value: This study fills a significant gap by offering a deeper understanding of the experiences of international researchers in Japanese companies, and by delivering insight and practical implications for policy considerations and talent management strategies in a rapidly evolving and increasingly globalized labor market.