Purpose : This paper attempts to understand the influence of appropriability of core technologies, overall technological capabilities of the firm, and network activities for the use of external resources, on entrepreneurial performance of technology startups. Research design, data, methodology : The study was verified in October and November, 2020 with 124 valid questionnaires excluding missing values in 163 surveys of founders and startup members of technology startups centered in Seoul TechnoPark clusters. Results : The analysis shows that appropriability has significant impact especially on market networks, which are links within the supply chain. It can be understood that appropriability's function of signalizing technological competence and function of coordinating technology cooperation have more profound impact on activating the network than technology protection does, which is the basic function of appropriability. Conclusions : Technology startups can improve their overall technological capabilities and achieve their entrepreneurial performance by procuring external resources and information, especially through market network activities, with their own ability to appropriate core technology assets. Therefore, in fostering technology start-up companies and born globals, it is necessary to strengthen support on various aspects of appropriability and network activities.