Metabolic enzymes, critical for cellular homeostasis, are frequently co-opted in a disease-specific manner to drive cancer progression. Here, we identify aldo-keto reductase family 1 member B10 (AKR1B10), down-regulated in gastrointestinal cancers, as a pivotal metastasis suppressor correlating with improved colorectal cancer (CRC) prognosis. Mechanistically, AKR1B10 activates protein phosphatase 2A (PP2A) by preventing redox-regulated nitration of its B56α subunit, preserving holoenzyme assembly and enabling c-Myc dephosphorylation at serine-62. Loss of AKR1B10 disrupts this pathway, stabilizing c-Myc, which drives integrin signaling and metastatic dissemination in CRC. We further demonstrate that lysine-125 of AKR1B10 is essential for its interaction with PP2A-Cα and B56α nitration, thereby attenuating CRC metastatic aggressiveness. Pharmacological restoration of PP2A activity effectively mitigates metastasis associated with AKR1B10 loss. In addition, c-Myc transcriptionally represses AKR1B10, establishing a feedback loop that sustains its down-regulation and enhances metastatic progression. This study uncovers an antimetastatic mechanism involving AKR1B10-mediated PP2A activation and highlights its potential as a biomarker and therapeutic target.