Anisotropic Ag2S‐edged Au‐triangular nanoprisms (TNPs) are constructed by controlling preferential overgrowth of Ag2S as plasmonic photocatalysts for hydrogen generation. Under visible and near‐infrared light irradiation, Ag2S‐edged Au‐TNPs exhibit almost fourfold higher efficiency (796 µmol h−1 g−1) than those of Ag2S‐covered Au‐TNPs (216 µmol h−1 g−1) and pure Au‐TNPs in hydrogen generation. A single‐particle photoluminescence study demonstrates that the plasmon‐induced hot electrons transfer from Au‐TNPs to Ag2S for hydrogen generation. Finite‐difference‐time‐domain simulations verify that the corners/edges of Au‐TNPs are high‐curvature sites with maximum electric field distributions facilitating hot electron generation and transfer. Therefore, Ag2S‐edged Au‐TNPs are efficient plasmonic photocatalyst with the desired configurations for charge separation boosting hydrogen generation. Anisotropic Ag2S‐edged Au‐triangular nanoprisms (TNPs), exhibiting almost four‐fold higher efficiency than Ag2S‐covered ones in hydrogen generation under visible‐NIR light irradiation, are synthesized by controlling preferential overgrowth of Ag2S. Single‐particle photoluminescence and finite‐difference‐time‐domain studies demonstrate that Ag2S‐edged Au‐TNPs have the desired configuration for plasmon‐induced hot electron transfer and charge separation, leading to highly efficient hydrogen generation.