The exploration of cost-effective yet high-efficiency inexpensive electrocatalysts for the hydrogen evolution reaction (HER) is of critical significance for future renewable energy conversion technologies. A feasible electrospinning strategy to construct a novel 1D hierarchical nanoarchitecture comprising Ni3Fe nanoalloy-encapsulated carbon nanotubes grown onto N-doped carbon nanofibers (abbreviated as Ni3Fe@N-C NT/NFs) is demonstrated here. Benefiting from the abundant firmly immobilized Ni3Fe nanoparticles for catalytic sites and hierarchical fibrous nanostructures for effective electron transport and mass diffusion, the resultant Ni3Fe@N-C NT/NFs display an extraordinary HER activity with a low overpotential of 72 mV to reach a current density of 10 mA cm(-2) in KOH medium and a remarkable stability for 40 000 s. Theoretical studies corroborate that the resultant Ni3Fe@N-C NT/NFs exhibit a favorable Gibbs free energy of hydrogen adsorption (Delta G(H*) = -0.14 eV), further manifesting their superior HER activity. The present work will advance the development of highly efficient nonprecious electrocatalysts for energy conversion.