Commercial vehicles predominantly employ drum brakes because of their low cost, robustness, and simple construction. However, with the increasing push toward quieter powertrains, particularly in electric commercial vehicles, brake squeal has become a dominant noise source. The inherent complex and chaotic nature of brake squeal makes its prediction and suppression especially challenging. Traditional squeal mitigation strategies, such as modifying component mass and stiffness or using materials with higher native damping (e.g., cast iron), are inherently constrained in their capacity to mitigate instability. In such scenarios, constrained layer damping (CLD) shims have proven to be an additional, effective and practical solution in disc brakes, which is motivating growing interest in extending similar concepts to drum brake applications. A key challenge in adopting shims for drum brakes lies in identifying and achieving the required damping level necessary to suppress squeal while adhering to stringent packaging, manufacturability, and cost constraints of foundation brakes. Establishing a clear relationship between squeal propensity, noise intensity, and target damping is therefore essential. While past CLD studies discuss layer-thickness effects in generic structures and caliper brakes, no work applies thickness optimization to brake shims in a drum brake assembly. This paper presents a systematic and target-driven framework for the design of CLD shims for drum brake applications. The approach initially defines the damping requirement for squeal suppression using system noise metrics and dynamic stability evaluations. Based on this requirement, a design optimization approach is employed to determine the appropriate thickness distribution of the individual shim layers, while accounting for practical constraints such as packaging limitations, material feasibility, and manufacturing considerations inherent to foundation brake systems. The optimized CLD shim configurations obtained through this process are subsequently integrated into the drum brake assembly and evaluated using complex eigenvalue analysis. The simulations utilized a validated FE model of the S-cam drum brake assembly, whose accuracy was established through experimental modal analysis–based correlation. The results indicate that the proposed target-based shim design methodology leads to a measurable improvement in modal damping and system stability, thereby demonstrating its effectiveness as a practical and robust approach for brake squeal mitigation in drum brake systems.