Constructing monodispersed metal sites in heterocatalysis is an efficient strategy to boost their catalytic performance. Herein, a new strategy using monodispersed metal sites to tailor Pt‐based nanocatalysts is addressed by engineering unconventional p–d orbital hybridization. Thus, monodispersed Ga on Pt3Mn nanocrystals (Ga‐O‐Pt3Mn) with high‐indexed facets was constructed for the first time to drive ethanol electrooxidation reaction (EOR). Strikingly, the Ga‐O‐Pt3Mn nanocatalyst shows an enhanced EOR performance with achieving 8.41 times of specific activity than that of Pt/C. The electrochemical in situ Fourier transform infrared spectroscopy results and theoretical calculations disclose that the Ga‐O‐Pt3Mn nanocatalyst featuring an unconventional p–d orbital hybridization not only promote the C−C bond‐breaking and rapid oxidation of ‐OH of ethanol, but also inhibit the generation of poisonous CO intermediate species. This work discloses a promising strategy to construct a novel nanocatalysts tailored by monodispersed metal site as efficient fuel cell catalysts. The monodispersed Ga site tailored Pt3Mn nanocatalyst based on high‐indexed facets was constructed and shows excellent EOR performance with high activity and selectivity towards the C2 reaction pathway, which was attributed to the unconventional p–d orbital hybridization and atomic‐level interface synergy.