The prolonged operation of high-energy-density lithium (Li) metal batteries (LMBs) hinges on reactivating irreversible Li (i.e., dead Li comprises isolated-Li0 debris and residual SEI), not just preventing its formation. However, concurrently achieving dead-Li suppression and rejuvenation remains challenging. Here, we design an N-doped hierarchically porous carbon (NHPC) host that enables bottom-up, uniform Li deposition via its interconnected ordered porosity and lithiophilic N-dopant sites, reducing dead Li formation. Notably, the lifespans of LiFePO4 cells using NHPC hosted Li is increased by 3 times, where limited dead Li that is dominated by isolated Li0 (a more reactivatable dead Li source) accumulates in NHPC. The porous structure of NHPC induces thin solid-electrolyte interphase, spatially confines dead Li and provides abundant electronic conducting pathways. These features collectively promote the electronic reconnection of isolated Li0 with the electrode by applying a facile resting protocol, recovering 28.3% Li loss and further extending the lifespan of NHPC@Cu||LiFePO4 cells by another ~100%. The feasibility of NHPC host can further be translated into low-temperature and pouch cells that suffer worse dead-Li issues. This work offers a new design perspective for functional hosts to revive dead Li and advance long-life Li metal batteries.