In the preliminar y design of magnetorheological dampers, conventional methodologies traditionally treat the mechanical modeling of damping forces and the theoretical computation of magnetic circuits as decoupled processes. These fragmented approaches often necessitate iterative finite element analysis for magnetic circuit parameter optimization, which not only extends the design cycle but also complicates the seamless integration of magnetic and mechanical domains. To overcome these limitations, this study introduces an integrated electro-magnetic-mechanical design framework for MR dampers, leveraging a distributed parameter approach to unify multiphysics modeling. First, a distributed parameter model is formulated to characterize the magnetic field distribution within the MR damper. Building upon the derived equivalent magnetic circuit, a set of equations governing the magnetic flux density across the damping channel is rigorously derived. Second, by integrating the nonlinear constitutive relationships of MR fluids, the magnetic field model is seamlessly coupled with the mechanical damping model, establishing a unified electro-magnetic-mechanical design framework. Subsequently, comprehensive numerical simulations are performed on both the standalone magnetic model and the fully coupled system to validate their theoretical consistency and predictive accuracy. Finally, prototype dampers are fabricated and experimentally evaluated under dynamic loading conditions to assess their real-world performance characteristics. Experimental results reveal that the damping behavior of the MR damper designed via the proposed distributed parameter methodology demonstrates remarkable congruence with measured data, thereby furnishing robust validation of the design approach’s accuracy. This investigation not only establishes a rigorous theoretical framework for the systematic design of MR dampers but also presents a scalable methodological blueprint applicable to a broad spectrum of engineering contexts.