Adhesion of proteins and bacteria was reduced by a factor close to one order of magnitude, and adhered bacteria were dramatically damaged on copper surfaces by grafting a PEG-modified PMMA-based (polymethyl methacrylate) copolymer together with an antimicrobial peptide. To obtain PEG and a peptide grafted together on the surface, a UV sensitive copolymer (containing PMMA, PEG and a UV sensitive reagent) was primary synthesized and deposited. After selective UV irradiation of this copolymer layer, an antimicrobial peptide, Magainin I, was grafted onto freed-polymer coated-copper surface via a spacer molecule (a mercapto carboxylic acid). The functionalization was characterized at each step by Polarization Modulation Reflection Absorption Infrared Spectroscopy (PM-RAIRS). The antiadhesive properties of the copolymer layer and antibacterial activity of the anchored Magainin I, were individually tested toward adsorption of bovine serum albumin (BSA) proteins, and against Gram positive bacteria, Listeria ivanovii, respectively. The results revealed that adhesion of both proteins and bacteria has been considerably reduced; moreover, the peptide still displays some antimicrobial activity after grafting. This work gives new ideas and perspectives to elaborate complex surface coatings where several agents are needed like for anti-biofilm or sensing applications.