In the current work, poly(4-vinylpyridine) (P4VP) was grafted on a macroporous polystyrene resin via free-radical polymerization by using the pendent vinyl group. The grafting conditions such as swelling agent, initiator concentration, reaction temperature, and amount of 4-vinylpyridine (4VP) monomer were optimized, and three resins with different 4VP monomer amounts (SC-1, SC-2, and SC-3) were chosen as adsorbents. P4VP-grafted resins were characterized by scanning electron microscopy, N-2 sorption/desorption isotherms, Fourier transform infrared, and X-ray photoelectron spectroscopy. The sorption properties of 2-naphthalenesulfonic acid (NSA) on three resins were comparatively investigated. The experimental data revealed that the sorption process on three resins fitted well with the pseudo-second-order kinetics equation, and the equilibrium isotherms were in good agreement with the Langmuir model. The NSA sorption onto resins was an endothermic and spontaneous process, and SC-3 loaded with NSA can be efficiently regenerated by NaOH and ethanol mixed solution after sorption. The maximum sorption capacities of three resins indicated that P4VP-grafted resins possess good sorption ability toward NSA.