High activity and stability are two requisites for a high-performance electrocatalyst but usually have to be balanced. CoS2 is regarded as an alternative electrocatalyst for the hydrogen evolution reaction (HER) but its HER activity and durability still cannot meet the criteria for practical applications. Here, we develop a strategy to simultaneously boost the HER activity and durability of CoS2 by fabricating polycrystalline nanowire (PCNW) arrays with dual doping of Fe and P. Systematic investigations demonstrate that Fe incorporation increases the active sites, while P substitution significantly boosts chemical and mechanical stability as well as HER kinetics. PCNW arrays provide abundant accessible active sites and allow for prompt gas release. As a result, Fe/P-CoS2 PCNW exhibits excellent HER performance with a low overpotential of 80 mV at 10 mA cm−2 and robust durability in acidic media. Such a strategy may provide opportunities for designing efficient and durable HER electrodes for practical water splitting.