<p>The effective and selective extraction of copper ions (Cu²⁺) from industrial wastewater is vital for environmental protection and resource recovery. This study reports iminodiacetic acid (IDA)-functionalized starch-based hydrogel microspheres (SHM-g-IDA) for high-performance Cu²⁺ adsorption. The adsorbent was synthesized via free-radical polymerization combined with molecular bridging, using glycidyl methacrylate (GMA) to covalently conjugate IDA to a starch–polyvinyl alcohol network. A well-defined spherical morphology was achieved by optimizing the coagulation process in a dimethyl sulfoxide bath. Structural characterization confirmed successful IDA grafting, yielding a material with a hierarchical porous architecture that facilitates rapid ion diffusion and delivers enhanced compressive strength (5.32&#xa0;MPa). Under optimal conditions (pH 5.0, 298&#xa0;K), SHM-g-IDA exhibits a maximum Langmuir adsorption capacity of 285.7&#xa0;mg&#xa0;g⁻¹ for Cu²⁺ (<i>R</i>^<i>2</i> = 0.995), while the adsorption kinetics closely follow the pseudo-second-order model (<i>R</i>^<i>2</i> = 0.999), indicating chemisorption via IDA–Cu²⁺ chelation as the rate-limiting step. Thermodynamic analysis confirmed the spontaneous and endothermic nature of the chemisorption process. Remarkably, the adsorbent shows exceptional selectivity in competitive multi-ion environments, with separation factors (<i>β</i>_<i>Cu/M</i>) up to 20.30, and maintains 88.1% of its initial capacity after six consecutive cycles, demonstrating outstanding reusability. These findings establish SHM-g-IDA as a highly efficient and sustainable platform for selective copper recovery from complex wastewater streams.</p>