In this article, photo-induced synthesis of poly (butyl acrylate)-grafted sodium salt of partially carboxymethylated sodium alginate (Na-PCMSAg- PBA) using ceric ammonium nitrate (CAN) as a photo-initiator has been reported for the first time. In order to optimize the photo-graft copolymerization reaction, the reaction variables such as concentrations of butyl acrylate (BA) monomer, photo-initiator, and nitric acid (HNO3) as well as the amount of backbone, reaction time, and temperature have been varied systematically and studied their influence on grafting yields viz. percent grafting (%G) and grafting efficiency (%GE). Under the optimum reaction conditions, the grafting yields obtained are %G = 220.85 and %GE = 97.81, and %Hp 2.19. Evidence of grafting has been examined spectroscopically, thermally and morphologically. The photo-synthesized novel graft copolymer (Na-PCMSA-g-PBA) may find its potential applications as metal adsorbent.