ABSTRACT The development of electrocatalysts with high activity and low precious‐metal contents is essential for efficient hydrogen production in the entire pH range. Herein, a Pt/NiCoP/carbon felt (CF) composite self‐supporting catalyst was constructed via electrodeposition of small Pt nanoparticles using inexpensive CF as a carrier and pre‐grown NiCoP as a substrate. High‐efficiency catalytic hydrogen evolution reaction (HER) was realized in the entire pH range. In electrolytes containing 1 M KOH, 0.5 M H 2 SO 4 , and 1 M phosphate‐buffered saline, the overpotentials (η 10 ) of HER driven by Pt/NiCoP/CF were as low as 22, 22, and 12 mV, respectively, which were better than those of a commercial Pt/C catalyst. The current density of Pt/NiCoP/CF‐catalyzed HER did not change significantly after a continuous operation for 100 h. In addition, the catalytic performance of Pt/NiCoP/CF for HER conducted in real seawater, seawater containing a supporting electrolyte, and simulated seawater was better than that of the commercial Pt/C catalyst. Furthermore, Pt/NiCoP/CF achieved ampere‐level hydrogen production in an all‐electrolytic cell for HER with a cell voltage as low as 1.7 V at a current density of 1 A cm −2 . Density functional theory calculations revealed that the Pt‐doped NiCoP catalyst promoted electron transfer and improved the HER performance of Pt/NiCoP/CF in the entire pH range. This work provides an innovative idea for the development of efficient and stable noble metal and non‐noble metal composite catalysts and describes a potential self‐supporting catalyst for efficient electrolysis of water to produce hydrogen in the entire pH range.