The graft copolymerization of methyl acrylate onto poly(vinyl alcohol) (PVA) with a potassium diperiodatonickelate(IV) [Ni(IV)]-PVA redox system as an initiator was investigated in an alkaline medium. The grafting parameters were determined as functions of the temperature and the concentrations of the monomer and initiator. The structures of the graft copolymers were confirmed by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, differential scanning calorimetry, and thermogravimetric analysis. The Ni(IV)-PVA system was found to be an efficient redox initiator for this graft copolymerization. A single-electron-transfer mechanism was proposed for the formation of radicals and the initiation. Other acrylate monomers, such as methyl methacrylate, ethyl acrylate, n-butyl acrylate, and n-butyl methacrylate, were used as reductants for graft copolymerization. These reactions definitely occurred to some degree.