In this work, we demonstrate a versatile approach for the fabrication of a single-component polyelectrolyte layer with tunable thickness and functionality. Poly(ethylene glycol) methyl ether methacrylate (PEGMEMA) was copolymerized with either aminoethyl methacrylate (AMA) or methacrylic acid (MAA) to prepare statistical PEGMEMA copolymers carrying positive or negative charges, respectively. These polyelectrolytes were used in a conventional layer-by-layer assembly process followed by cross-linking to form a surface-grafted stable poly(PEGMEMA) layer carrying both negative and positive charges. To transform this layer into a single-component polyelectrolyte layer carrying just one type of ionizable group, the amino groups were quenched, thus leaving a single-component anionic PEGMEMA-based polyelectrolyte layer. Last, we demonstrate that compared to a zwitterionic layer, the anionic polyelectrolyte layer exhibits an enhanced protein-repelling property against bovine serum albumin (BSA).