Proton exchange membrane fuel cells (PEMFCs) offer an attractive solution to reduce the carbon emissions of the transport sector. Despite the continuous efforts of researchers over the past decades, the current landscape of fuel cell technologies shows limitations at the component level in terms of performance, durability, and production cost. The main objective of the work presented here is to improve the power density of fuel cells by understanding the performance limitations of the membrane electrode assemblies (MEAs). To accomplish this objective, a series of in‐situ performance tests and ex‐situ characterisation methods have been used to create correlations between the observed performance, voltage loss breakdowns at the cell level, and the fundamental material property characteristics of state-of-the-art (SoA) MEA components. Specifically, we have explored the development of graded catalyst layers in the x-, y-, and z-direction to improve catalyst utilization, leading to increased power density while simultaneously decreasing catalyst loadings. The optimized catalyst layer structures, in combination with ultrathin proton exchange membranes, have led to high performance MEAs with reduced catalyst loadings compared to commercially available SoA MEAs.