Purpose: The purpose of this study is to examine the effects of CEO's self-determination on entrepreneurship, business performance (operational and financial performance). Also, this research provide some strategic insights for improving business performance. In the proposed model, self-determination consists of autonomy, competence, and relatedness, and entrepreneurship consists of innovation, initiative and risk sensitivity, and proactiveness. More specifically, this study proposes a framework that entrepreneurship and operational performance will play mediating roles between self-determination and financial performance. Research design, data, methodology: In this study, an online survey was conducted on SME CEOs for analysis, and a total of 122 samples were used. In the analysis process for hypothesis verification and evaluation, frequency analysis was first performed to identify the demographic characteristics of the respondents, and confirmatory factor analysis was conducted to assess the reliability and validity of the measurement model. In addition, a structural model analysis was conducted to examine the structural relationships between CEO's self-determination, entrepreneurship, and business performance (operational and financial performance) using SmartPLS 3.0. Results: The findings and summary are as follows. First, the autonomy of self-determination has a positive effect on entrepreneurship. Second, the competence of self-determination affects entrepreneurship and operational performance. Third, it affects the innovation, initiative and risk sensitivity of the CEO's entrepreneurship, and ultimately, its operational performance. The results show that the business performance of Start-up also increases when self-determination can be a factor in increasing entrepreneurship in three sub-dimensionalities. Conclusions: The conclusion of this study is that in order for SMEs to develop into a sustainable company by securing competitiveness after start-up, external motivation such as external help and support from the state (local government) is important, but competence and relationship, which are components of self-determination. The intrinsic motivation of the CEO may be more important. To this end, CEO's should prioritize learning for competency development, and the government should pay attention to providing various educational programs through establishment of education policies and education systems to enhance the competency of start-up CEO's.