A nitrogen-doped carbon catalyst enables selective urea electrosynthesis through sequential reduction of nitrate and carbon dioxide. The catalyst facilitates dynamic switching between nitrate and carbon dioxide reduction pathways, enhancing C–N coupling and minimizing side reactions. This approach achieves a urea yield rate of 596.1 µg mg⁻¹ h⁻¹ with a Faradaic efficiency of 62% at -0.5 V versus RHE. The mechanism is supported by in situ spectroscopic techniques and theoretical calculations, revealing that proton-involved dynamic catalyst evolution reduces reactant reduction and minimizes side products. The catalyst's performance is attributed to its ability to reversibly hydrogenate nitrogen species, enabling sequential reduction and efficient urea formation. In contrast, a Cu₁/NC catalyst shows lower urea selectivity due to competition between nitrate and carbon dioxide reduction. The study highlights the importance of dynamic active sites in electrocatalysis for selective urea synthesis.A nitrogen-doped carbon catalyst enables selective urea electrosynthesis through sequential reduction of nitrate and carbon dioxide. The catalyst facilitates dynamic switching between nitrate and carbon dioxide reduction pathways, enhancing C–N coupling and minimizing side reactions. This approach achieves a urea yield rate of 596.1 µg mg⁻¹ h⁻¹ with a Faradaic efficiency of 62% at -0.5 V versus RHE. The mechanism is supported by in situ spectroscopic techniques and theoretical calculations, revealing that proton-involved dynamic catalyst evolution reduces reactant reduction and minimizes side products. The catalyst's performance is attributed to its ability to reversibly hydrogenate nitrogen species, enabling sequential reduction and efficient urea formation. In contrast, a Cu₁/NC catalyst shows lower urea selectivity due to competition between nitrate and carbon dioxide reduction. The study highlights the importance of dynamic active sites in electrocatalysis for selective urea synthesis.