Nowadays, moving toward more lightweight designs is the key goal of all major automotive industries, and they are always looking for more mass saving replacements. In this study, a new methodology for the design and optimization of cross-car beam (CCB) assemblies is proposed to obtain a more lightweight aluminum design as a substitution for the steel counterpart considering targeted performances. For this purpose, first, topology optimization on a solid aluminum geometry encompassing the entire design space should be carried out to obtain the element density distribution within the model. Reinforcing locations with high element density and eliminating those with density lower than the threshold value result in the conceptual design of the CCB. To attain the final conceptual design, the process of topology optimization and removal of unnecessary elements should be addressed in several steps. By taking advantage of shape and size optimizations, the conceptual model is finalized in details satisfying defined criteria. The proposed design and optimization framework is tested on the design of a specific CCB considering the allowable dimensions, weight as the fitness function, and noise, vibration, and harshness (NVH) performance as the constraint. The new solution shows better fitness value and NVH performance compared to the existing design, which advocates the effectiveness of the suggested approach.