The development of dual-function catalysts with high activity and durability is essential in overall water splitting applications. In this work, FeCoNiPtRu HEA was rapidly synthesized on carbon support by carbothermal shock process. The synergistic interaction among metal elements enhanced the catalytic activity. The catalyst demonstrated overpotentials of 104 mV for HER and 331 mV for OER at 10 mA cm−2. In addition, FeCoNiPtRu HEA was aimed on carbon paper and the nanoparticles were encapsulated by a carbon layer with a stability of up to 100 h. Finally, as a dual-function catalyst, when applied as both the cathode and anode in overall water splitting (OWS), FeCoNiPtRu demonstrated a voltage of 1.69 V at 10 mA cm−2. This work demonstrates the significant potential of high-entropy alloy catalysts in hydrogen production through overall water splitting.