<p>With the advancement of the high-tech manufacturing industry, the importance of machining technology for high-hardness steels—known for their excellent wear and impact resistance—has been increasing. In particular, as the demand for machining SKD11, a material commonly used in cold-press molds, continues to grow, there has been active research into developing cutting tools with superior cutting performance and wear resistance. Typically, cutting tool development involves designing the tool’s geometry and material, fabricating samples, and validating them through experimental methods. However, this approach is time-consuming and costly. Therefore, to identify the causes of tool wear and improve tool performance, a numerical analysis approach is required to microscopically investigate cutting characteristics. In this study, the cutting performance was analyzed through finite element analysis (FEA) simulations, focusing on the influence of secondary rake face and edge radius—two major factors affecting tool wear during high-hardness steel machining. The simulation results showed that a wider secondary rake face facilitates smoother chip evacuation and reduces cutting forces. Additionally, an inverse relationship was observed between edge radius and both tool stress and cutting temperature. Notably, the type C (Intermediate with Chipbreaker) geometry, which incorporates a strategically designed shallow groove, addressed the mechanical stability limitations associated with an expanded secondary rake face. It also enabled stable chip curvature control, thereby enhancing both tool life and machining stability. This study numerically identified the importance and impact of selected geometric elements in high-hardness steel machining and derived optimal design strategies to minimize tool wear and improve machining efficiency. The findings are expected to provide useful guidelines for the design and optimization of cutting tools tailored to high-hardness steel applications.</p>