Active neck musculature plays an important role in the response of the head and neck during impact and can affect the risk of injury. Finite element Human Body Models (HBM) have been proposed with open and closed-loop controllers for activation of muscle forces; however, the controllers in many current models are often calibrated to specific experimental loading cases, without considering the intrinsic role of physiologic muscle reflex mechanisms under different loading conditions. The goal of this study was to develop a closed-loop controller for a contemporary male HBM to represent muscle activation mechanisms based on the vestibulocollic and cervicocollic reflexes. Dual PID controllers were implemented, with head rotation and muscle stretch used for input.Controller parameters were optimized using volunteer data and then independently assessed across twelve impact conditions. The kinematics from the closed-loop controller simulations showed good average correlations to the experimental data (0.699) for the impacts. Compared to a previous optimized open-loop activation strategy, the average difference was less than 9%. The incorporation of the reflex mechanisms using a closedloop controller can provide robust performance for a range of impact directions and severities, which is critical to improving HBM response under a larger spectrum of automotive impact simulations.