The use of sustainable energy is of great importance in today’s world due to environmental issues and the lack of fossil fuels. Proton-exchange membrane fuel cells are a potential solution. The catalyst‐to‐ionomer ratio and the hot-press load are two important parameters that substantially affect the performance of the membrane electrode assembly. If the catalyst-to-ion-ion-ion-ion-ionomer ratio is too high, it can impair material bonding and cause uneven catalyst distribution; if it is too low, it can result in poor performance due to an insufficient catalyst amount. Likewise, too high a hot-press load can damage the porous catalyst layer, while too low a hot-press load increases the contact resistance between the catalyst-coated membrane and the gas diffusion layer. Optimization studies were performed on a 6.25 cm2 proton exchange membrane fuel cell with catalyst coated membrane-membrane electrode assembly at a loading of 0.15 mgPt cm-2. The best performance was achieved at a catalyst-ionomer ratio of 3:1 and a hot-press load of 160 kg. The statistical analysis with interaction plots and derived equations confirmed the correlation between the deviation value of 710 W m-2 (summed individual impact and integrated effect) and the traditional interaction effect value of 355 W m-2 (ratio of 2) and confirmed by the experimental results. The typical interaction effects are theoretically straightforward, and the deviation value provided here better depicts the influence of parameter interactions and provides a more reliable tool for performance measurement. The optimized catalyst-coated membrane electrode assembly showed a 5.8% improvement compared with a commercial membrane electrode assembly, mainly due to the optimized catalyst-to-ionomer ratio and hot-press load parameters. This work improves quantification and introduces a new evaluation metric, the deviation value, which can be extended to larger proton-exchange membrane fuel cell stacks, enabling a significant advance in the fundamental understanding of membrane electrode assembly design and in its practical application to sustainable energy systems.