Here we present a fundamental investigation of a conceptual strategy for simultaneously strengthening the tolerance to radical degradation, and improving the proton conduction capability, of polymer electrolyte membranes (PEMs) for fuel cells. A random disulfonated polyimide (SPI) containing 1 wt% of hydrophilic silica nanoparticles is used as a polymer matrix model, for dispersing boehmite nanoparticles, with the help of a non-ionic surfactant, L92. The mixture of boehmite and L92 in the micelle form results in enhanced boehmite distribution to a certain content. Boehmite nanoparticle acts as an inorganic scavenger to decompose hydrogen peroxide, known as a radical presursor, and as an inorganic conductor to transport protons owing to their acidity in PEMs. When proton conductivity and electrochemical single cell performance are considered, the optimal boehmite content chosen in this study is 2 wt% in the SPI matrix. This study provides valuable information on the rational design of chemically durable and proton-conductive fuel cell membrane materials.