[en] A classical potential for ZrC is developed in the form of a modified second-moment approximation with emphasis on the strong directional dependence of the C-Zr interactions. The model has a minimal set of parameters, 4 for the pure metal and 6 for the cross interactions, which are fitted to the database of cohesive energies of B1-, B2-, and B3-ZrC, the heat of formation, and most importantly, the atomic force constants of B1-ZrC from first-principles calculations. The potential is then extensively tested against various physical properties, none of which were considered in the fitting. Finite temperature properties such as thermal expansion and melting point are in excellent agreement with experiments. We believe our model should be a good template for metallic ceramics