Renewable-powered electrocatalytic CO₂ conversion to long-chain hydrocarbons represents a sustainable path to produce chemicals and fuels. However, recently discovered systems still lack C–C coupling capabilities required to yield longer, more valuable carbon chains. This study reports cobalt catalysts with a focus on a Co₃O₄-derived material for the selective conversion of CO₂ to C₁–C₇ hydrocarbons, following an Anderson–Schulz–Flory distribution. The obtained chain growth probability (α) of 0.54 substantially exceeds that of any other known electrocatalyst, which ranged from 0.2 to 0.4. Detailed in situ characterization and simulations indicated that Co-Co₃O₄ interfaces, formed in situ during CO₂ electrolysis, are the active sites that promote enhanced chain growth. To prevent overreduction that causes the deactivation of these interfacial sites, the electrode is exposed to intermittent short reoxidation cycles during CO₂ electrolysis. Consequently, the catalyst regained its oxidic phase and ability to form hydrocarbons. Overall, this study opens new frontiers in the one-step conversion of CO₂ into multi-carbon products and suggests the exploration of metal–metal oxide interfaces as a promising strategy for further progress.