WC–Co cemented carbides are widely used in cutting tools, mining drilling, and high-temperature wear-resistant components because of their excellent hardness, wear resistance, and fracture toughness. However, their frictional and oxidative stability directly impacts service life and poses a critical limitation under extreme operating conditions. This study systematically investigates the effects of TaC addition on the microstructure, friction and wear behavior, and oxidation resistance of WC–6Co cemented carbides. Results indicate that TaC effectively refines WC grains and improves microstructural homogeneity. When the TaC content reaches 0.6 wt%, the alloy demonstrates the best wear resistance, with a wear mass loss reduced to 0.15 mg and a stable coefficient of friction of approximately 0.3. Nevertheless, excessive TaC leads to the formation of brittle phases, compromising toughness and degrading wear performance. Oxidation tests reveal that increasing TaC content reduces the oxide layer thickness from 4.05 μm to 2.69 μm at 0.9 wt%, forming denser and more uniform oxide products that effectively hinder oxygen diffusion and slow the oxidation rate. This work elucidates the strengthening and protection mechanisms imparted by TaC and provides both theoretical insights and experimental guidance for designing high-performance cemented carbides for demanding high-temperature applications.