<p>To enhance the machinability of high-hardness Cr12MoV die steel, systematic investigations were conducted on the milling, drilling, and surface polishing performance of Cr12MoV steels with varying tellurium (Te) contents. Cutting forces during milling and axial forces during drilling were quantitatively measured using a dynamometer, while surface finish after milling and polishing was characterized through surface roughness measurements. The inclusions in specimens were analyzed via optical microscopy (OM), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and electron probe microanalyzer (EPMA). The study demonstrates that Te addition effectively reduces the aspect ratio of inclusions, promoting their transition to near-spherical morphologies. Composite inclusions consisting of MnTe-encapsulated MnS and Al₂O₃ were identified in the steel matrix. At elevated Te concentrations, discrete MnTe particles formed preferentially. The modified inclusions significantly improved machining performance by reducing cutting forces during milling and drilling operations. A positive correlation was observed between Te content and surface finish quality, with superior surface integrity achieved at higher Te levels. Furthermore, Te addition markedly enhanced chip morphology during drilling, demonstrating improved chip-breaking efficiency. Te can also improve the polishing performance of die steel, with superior results achieved at higher Te content.</p>