This study proposed a manufacturing strategy model consisting of three domains—the environmental domain, the core competency domain, and the manufacturing strategy domain—based on existing manufacturing strategy models, in order to investigate the process of determining the dimensions of manufacturing strategy. The internal consistency among these domains was empirically verified using data from domestic electronics manufacturing firms. The study particularly focused on identifying the role of core competency factors in the process of determining manufacturing strategy dimensions. The analysis results showed that the dimensions of manufacturing strategy importance variables for domestic electronics firms consisted of flexibility, quality, and delivery/price factors, with the price dimension of competitiveness indicators tending to be integrated into the delivery dimension. Furthermore, core competencies had a greater influence than the external environment on determining the priority of manufacturing strategy importance dimensions for domestic electronics firms, and product competitiveness in particular served as a moderating variable between the environment and manufacturing strategy importance dimensions. These results suggest that the dimensions of manufacturing strategy for domestic electronics firms are shifting from price- and quality-centered strategies to flexibility-centered strategies as the competitive environment intensifies, and that product competitiveness is accelerating this process.