We present an approach for quantifying the flow stress of metals under dynamic loads, based on experiments that involve distinct but related physical phenomena. In modified Taylor tests, a stress-wave generated velocity–time signal is measured, which indirectly provides information on the plastic deformation behavior of the tested material at high strain rate. The Johnson–Cook plasticity model is calibrated for a high-strength steel on the basis of such measurements in combination with quasi-static and dynamic tensile test data. The plasticity model parameters are found with differential evolution through the inverse optimization of material test simulations. A consistent set of model parameters is identified that reproduces measurements from all types of tests. The obtained plasticity model features a small initial yield stress, which is compensated by large strain hardening so as to produce a realistic engineering yield stress. An independent calibration method is employed, by regression of the model on quasi-static and dynamic tensile test results, that confirms the validity of the plasticity model parameter values.