One plausible approach to endow aerogels with specific properties while preserving their other attributes is to fine‐tune the building blocks. However, the preparation of metallic aerogels with designated properties, for example catalytically beneficial morphologies and transition‐metal doping, still remains a challenge. Here, we report on the first aerogel electrocatalyst composed entirely of alloyed PdNi hollow nanospheres (HNSs) with controllable chemical composition and shell thickness. The combination of transition‐metal doping, hollow building blocks, and the three‐dimensional network structure make the PdNi HNS aerogels promising electrocatalysts for ethanol oxidation. The mass activity of the Pd83Ni17 HNS aerogel is 5.6‐fold higher than that of the commercial Pd/C catalyst. This work expands the exploitation of the electrocatalysis properties of aerogels through the morphology and composition control of its building blocks. Function follows form: Aerogel electrocatalysts consisting of alloyed PdNi hollow nanospheres (HNS) were prepared. Their chemical composition and shell thickness can be controlled based on the ratio of the Ni/Pd precursors. The mass activity of the Pd83Ni17 HNS aerogel is 5.6 times higher than that of the commercial Pd/C catalyst.