Abstract Anode‐less all‐solid‐state batteries (ASSBs) are being targeted for next‐generation electric mobility owing to their superior energy density and safety as well as the affordability of their materials. However, because of the anode‐less configuration, it is nontrivial to simultaneously operate the cell at room temperature and low pressure as a result of the sluggish reaction kinetics of lithium (de)plating and the formation of interfacial voids. This study overcomes these intrinsic challenges of anode‐less ASSBs by introducing a dual thin film consisting of a magnesium upper layer with a Ti 3 C 2 T x MXene buffer layer underneath. The Mg layer enables reversible Li plating and stripping at room temperature by reacting with Li via a (de)alloying reaction with a low reaction barrier. The MXene buffer layer maintains the electrolyte‐electrode interface by inhibiting the formation of voids even at low pressure of 2 MPa owing to the high ductility of MXene. This study highlights the importance of a combined chemical and mechanical approach when designing anode‐less electrodes for practical adaptation for anode‐less ASSBs.