AbstractThe surging demand for environmental‐friendly and safe electrochemical energy storage systems has driven the development of aqueous zinc (Zn)‐ion batteries (ZIBs). However, metallic Zn anodes suffer from severe dendrite growth and large volume change, resulting in a limited lifetime for aqueous ZIB applications. Here, it is shown that 3D mesoporous carbon (MC) with controlled carbon and defect configurations can function as a highly reversible and dendrite‐free Zn host, enabling the stable operation of aqueous ZIBs. The MC host has a structure‐controlled architecture that contains optimal sp²‐carbon and defect sites, which results in an improved initial nucleation energy barrier and promotes uniform Zn deposition. As a consequence, the MC host shows outstanding Zn plating/stripping performance over 1000 cycles at 2 mA cm⁻² and over 250 cycles at 6 mA cm⁻² in asymmetric cells. Density functional theory calculations further reveal the role of the defective sp²‐carbon surface in Zn adsorption energy. Moreover, a full cell based on Zn@MC900 anode and V₂O₅ cathode exhibits remarkable rate performance and cycling stability over 3500 cycles. These results establish a structure‐mechanism‐performance relationship of the carbon host as a highly reversible Zn anode for the reliable operation of ZIBs.