Purpose - The purpose of this study is to identify the relations among perceived organizational support, career planning, and subjective career success (career satisfaction and job satisfaction). In particular, this study focuses on the mediating effect on the career planning between perceived organization and subjective career success. The target cases are employees of a Korean branch of a global company (A), which operates formal career program to support a career development for employees. Research design, data, and methodology - The data were collected from December, 2014 to March, 2015. 211 out of 300 questionnaires were returned (response rate 70.3%). After the data cleaning, 209 questionnaires were used for the data analysis. These data were analyzed through descriptive statistics, correlation analysis, exploratory factor analysis (EFA), confirmatory factor analysis (CFA), and structural equation modeling (SEM). The whole process of the data analysis was accomplished using the SPSS 21.0 for windows and the AMOS 21 program. Results - The findings of the study are as follows: First, the better the organizational support is perceived, the higher career satisfaction and job satisfaction is. That is, the employees' career and job satisfaction is higher, when they feel themselves received more supporting. Second, perceived organizational support has a positive impact on employees' career planning. This result means that it is important to support employees in their career development. Third, career planning has a positive impact on career satisfaction, but not on job satisfaction. Lastly, it is verified that career planning has a mediating effect between the perceived organizational support and career satisfaction. Not only has the perception of an organizational support a direct impact on career satisfaction, but also an indirect impact through career planning. However, there is not an indirect relationship through career planning, just an direct relationship between the perception of an organizational support and job satisfaction Conclusions - Based on the findings of this study, the major conclusion of the study was as follows: The study provides theoretical values and practical implications for the fact that the differences of the subjective perception about organizational support exist among employees, and the differences have an impact on their career planning as well as subjective career success. Furthermore, some recommendations for workplace were suggested: The companies should support the career development for employees in organization level. Even though employment instability makes individual workers themselves to be responsible for their own career development, it is an important issue in organizational level that employees' career success could have positive effects on organizational development and success, as well. However, there is a limit in the study that analyzing results cannot be generalized due to the data from a single company. Some recommendations for future research are suggested: First, a comparative study should be conducted with other various companies. Second, a hierarchical analyzing model needs to be applied to substantiate how organizational context influences on subjective career success of employees.