Nickel-based electrocatalysts have emerged as important alternatives to precious metal catalysts for alkaline water electrolysis because of their abundance, relatively low cost, electrical conductivity, and compatibility with alkaline operating environments. Considerable progress has been achieved through alloying, phase engineering, nanostructuring, defect generation, heterointerface construction, and electrode–substrate integration, particularly in Ni–Co, Ni–Mo, nickel sulfide, nickel phosphide, nickel oxide, and nickel hydroxide. However, reported improvements in electrocatalytic activity do not necessarily translate into efficient and durable hydrogen production under practical operating conditions. This review critically examines the relationship between Ni-based catalyst composition, structure, electrochemical reconstruction, catalytic activity, and long-term stability in alkaline water electrolysis. Attention is given to the dynamic transformation of Ni-containing surfaces during operation, the influence of Fe, Co, and Mo incorporation, structural and interfacial engineering, and the effects of catalyst architecture on mass transport and gas-bubble management. This critical review further evaluates the limitations of conventional low-current-density catalyst screening. It emphasizes high-current-density performance, full-cell voltage, Faradaic efficiency, electrode integrity, and long-term durability as more meaningful indicators of practical performance. Finally, it discusses the challenges associated with operating-state characterization, standardized testing, dynamic operation, scalable electrode fabrication, and translation from laboratory electrodes to practical electrolyzers. By connecting catalyst design with electrode engineering and electrolyzer-level performance, this review provides a framework for developing Ni-based electrodes capable of combining high activity, structural stability, and sustained hydrogen production under industrially relevant alkaline electrolysis conditions.