In existing rolling bearing dynamics modeling, the evolution of the impact force when the rolling element passes through the outer ring defect is not fully considered, resulting in systematic deviations in the analysis of the overall dynamic response characteristics of the bearing, making it difficult to accurately characterize its true performance status under actual operating conditions. To address this, a dynamic modeling method for local faults in rolling bearings that characterizes impact response is proposed. First, the motion process of the rolling element traversing an outer ring defect is analyzed, and a corresponding time-varying displacement excitation model is constructed accordingly. Second, based on the momentum theorem, the impact force function related to the defect length, depth, and rotational speed when the rolling element impacts the rear edge of the outer ring defect is derived. Integrating Hertzian contact theory, a dynamic model for local faults in rolling bearings that reflects impact response characteristics is constructed. Finally, taking the N6205 deep groove ball bearing as an example, the established model was verified through simulation and experiment, and the effects of different defect lengths, depths, and rotational speeds on the bearing’s dynamic characteristics were analyzed. The results show that, under operating conditions of 500 and 1 000 r/min, the errors between the simulated signal’s double-impact time interval and first harmonic characteristic and the theoretical values are both less than 0.6%, and the maximum error with the measured data does not exceed 3.23%. Simultaneously, the local impact generated during the contact between the rolling element and the outer ring defect has a significant impact on the bearing’s vibration response. This study can provide a reference for rolling bearing fault diagnosis and life assessment.