Developing efficient and stable electrocatalysts for seawater splitting remains a huge challenge because of low catalytic selectivity and poor resistance to chlorine‐induced corrosion. Here, we developed a nickel‐iron layered double hydroxide nanosheets doped with chromium and sulfur dual atoms (Cr,S‐NiFe LDH). Cr,S‐NiFe LDH exhibited low overpotentials of 321 and 406 mV at industrial current densities of 500 and 1000 mA cm −2 , respectively. An anion exchange membrane electrolyzer based on Cr,S‐NiFe LDH anode can maintain 2000 mA cm −2 @1.764 V for 100 h. Electronic structure analysis revealed that the sulfur doping facilitates electron transfer from nickel to sulfur sites, while chromium incorporation strengthens the electronic interactions between iron and chromium sites. This modification induced the formation of high‐valence nickel and chromium species, which favor seawater electrolysis. Mechanistic studies revealed that dual heteroatom doping modifies the local electronic environment of nickel/iron sites, repelling chlorine ions and optimizing the adsorption of oxygenated intermediates.