Power and cable carrier systems have been shown to significantly impact the dynamic behavior of lightweight space structures. The goal of this paper is to obtain an optimal cable placement geometry for cable-harnessed beam structures by minimizing the impact of added cables on the system dynamics. The cable is harnessed to the beam in a periodic pattern, which forms several repeating fundamental elements within the structure. An analytical model for the cable-harnessed beam, using an energy-equivalence homogenization method, is employed for the purpose of optimization. The natural frequencies of the cable-harnessed beam are then matched with the bare beam (when no cables attached) using an optimization algorithm to find the optimal cable placement solution for the given system parameters. Subsequently, the system parameters’ effects on the optimal solutions are investigated and discussed. Experimental modal analysis is then performed to further validate the optimal solutions found using the model. The test results further validate findings from the model, and the frequency response functions from the bare and optimally wrapped beams align really well.