<p>Metal-film-based conductors are an important element of flexible electronic devices. However, they typically suffer from fatigue damage and electrical degradation under cyclic deformation, which can limit practical use. Here we report fatigue-resistant metal films with a coherent gradient nanolayered architecture. The architecture consists of alternating stacked layers of silver and aluminium, with silver layers that become progressively thinner and finer grained. Initial crack nucleation is delayed by a combination of heterodeformation-induced strengthening, controlled grain coarsening in the silver layer and mitigation of interface stress concentrations. The moderate interface adhesion between silver and aluminium, and the multiaxial stress state induced by the gradient structure, also promote interface delamination and crack deflection, which suppresses fatigue-crack propagation. Our coherent gradient nanolayered silver/aluminium films exhibit a conductivity of over 10⁷ S m⁻¹ and relatively little conductivity change in both high-cycle, low-stress regimes (10⁷ cycles at 0.7% strain) and low-cycle, high-stress regimes (10⁵ cycles at 5% strain).</p>