To resolve the contradiction between demand for remediation-with-production systems in heavy metal management and scarcity of microbial agents with remediation and plant growth-promoting functions. This study isolated Enterobacter ludwigii N15, a urease-producing bacterium with plant growth-promoting traits. By coordinating its remediation and growth-promotion functions, N15 overcame the challenge of maintaining functional persistence under metal stress. Gradient stress experiments, biomineralization characterization, and genomic analyses revealed that N15 preferentially activated a tripartite defense system (exopolysaccharide barrier, sulfide precipitation, and thiol chelation) to counteract toxicity, followed by immobilizing heavy metals through urease-driven microbially induced carbonate precipitation (MICP). Under heavy metal stress, strain N15 retained capacities for indole-3-acetic acid (IAA) biosynthesis, siderophore production, and phosphate solubilization, thereby supporting plant growth promotion. The resulting nano-carbonate minerals exhibited secondary adsorption via active groups (CO32-). Pot experiments confirmed that N15 reduced Cd, Pb, and Zn content in pakchoi roots by 36.16 %-39.99 % and in leaves by 53.50 %-55.99 %, while enhancing the growth of plant roots (2.91-3.65 cm) and shoots (4.12-6.56 cm). N15 maintained system stability through Proteobacteria enrichment, with urease activity serving as the core regulatory node for soil pH optimization, heavy metal bioavailability reduction, and plant growth promotion. This work provides a scientific foundation for developing multifunctional bioagents supporting production and remediation strategies in heterogeneous environments.