One-dimensional tantalum carbide (TaC) nanorods are considered promising candidates for high-temperature electromagnetic wave (EMW) absorption because of their intrinsically high electrical conductivity and exceptional thermal stability. However, conventional synthesis approaches typically yield products with low quality and poor efficiency, limiting their practical applicability. Here, we report the rapid and scalable synthesis of high-quality TaC nanorods via a molten salt-assisted carbothermal reduction strategy integrated with microwave heating. The formation of well-defined one-dimensional TaC nanorods was achieved within 20 min at 1300 °C by precisely tuning the precursor composition (Ta₂O₅ : C : NaCl : Ni = 1 : 8 : 2 : 0.08). The resulting TaC nanorods exhibit notable EMW absorption properties, with a maximum effective absorption bandwidth (EAB_max) of 3.0 GHz at a simulated thickness of 1.0 mm and a minimum reflection loss (RL_min) of −30.5 dB. Off-axis electron holography reveals pronounced charge accumulation at the Ta₂O₅ shell/TaC core interface, indicative of interfacial polarization effects. Furthermore, radar scattering cross-section (RCS) simulations demonstrate substantial attenuation of the backscattered signal from a perfect electric conductor (PEC) substrate coated with the TaC layer, with the strongest electromagnetic energy dissipation observed at a coating thickness of 1.0 mm. These results underscore the viability of microwave-assisted synthesis as an efficient and sustainable route for producing high-performance TaC nanorods for EMW absorption applications under extreme thermal conditions.