Lanthanum-based adsorbents have garnered considerable attention for phosphate removal due to their superior adsorption capacities and environmentally benign nature. This investigation presents a facile hydrothermal method for the fabrication of two lanthanum-doped porous magnetic carbon microspheres, designated as MCMSs-LaEX and MCMSs-LaIN, which are derived from the Camellia oleifera shells. The adsorbents exhibit a mesoporous microsphere structure, as evidenced by SEM, TEM, and BET analysis. Furthermore, the effective integration of La(OH)3 and Fe3O4 is substantiated through XRD, FT-IR, and VSM analysis. The adsorption kinetics and isotherms were fitted well to the pseudo-second-order model and Freundlich model, respectively, indicating a multilayer chemisorption mechanism. The materials demonstrated excellent adsorption performance across a broad pH range of 2–7, coupled with notable selectivity towards phosphate ions amidst the presence of elevated concentrations of typical competitive anions in water. Moreover, the MCMSs-LaIN maintained an adsorption efficiency of 90% following four consecutive cycles of adsorption and desorption with a diluted NaOH solution, attesting to its durability and potential for reuse. In-depth XRD, FT-IR and XPS characterization results revealed that the adsorption process is primarily driven by ligand exchange between phosphates and La(OH)3. The observed reduction in pore volume post-adsorption suggested that the formation of LaPO4 precipitates likely leads to pore blockage within the adsorbent materials. Significantly, both adsorbents displayed exceptional efficacy in removing phosphate from intricate industrial wastewaters, including those generated during phosphating and electrophoresis operations, underscoring their practical applicability in environmental remediation.