Recent studies indicate that injury-induced dedifferentiation generates transient regenerative progenitors (TRPs), which support tissue repair across multiple organs, including the liver. In vivo partial reprogramming using Yamanaka factors (Oct4, Sox2, Klf4, and c-Myc; OSKM) produces intestinal TRPs closely resembling those arising from injury-induced dedifferentiation, but transgenic or viral approaches raise safety concerns because of prolonged expression. Here, we show that transient OSKM induction generates two distinct liver progenitor-like cell (LPLC) populations without injury and with limited activation of injury-associated immune responses. Single-nucleus RNA sequencing shows that one population resembles injury-induced LPLCs observed in acetaminophen-injured mouse and human livers. To develop a temporally controlled regenerative strategy, we establish a liver-targeted lipid nanoparticle system for OSKM mRNA delivery. OSKM mRNA-LNP treatment induces hepatocyte dedifferentiation and Sox9⁺ LPLC-like cell formation and is associated with enhanced regeneration after acetaminophen-induced injury. Together, these findings identify transient hepatic reprogramming as a strategy for inducing regenerative plasticity and support liver-targeted OSKM mRNA delivery as a potential approach for acute liver injury.