The purpose of this paper is to explore factors affecting career success of graduate students from Ho Chi Minh City Open University in Vietnam. By employing mixed research method with qualitative and quantitative techniques, we first conducted in-depth interview with 20 graduate students to find out factors that can affect their career success, and then quantitative data was collected with a survey of 436 graduate students in Vietnam. We employ Partial Least Squares Structural Equation Modeling (PLS-SEM) with Smart PLS 3.2 software to analyze the collected data. The finding suggests that individual competences, working experience, personal networks and organizational structure were crucial factors that influence objective career success, while individual aspirations and personal networks were important factors for subjective career success. The paper provides important implications for organizations and educational institutions to enhance career success of their workers.