Bacterial colonization and biofilm formation on indwelling medical devices potentially cause serious and life-threatening infections. Technologies to prevent bacterial colonization and biofilm formation on biomedical devices are in great demand. Here, we report the preparation of coating monomers by conjugating rosin acid-derived maleopimaric acid quaternary ammonium cation (MPA-N+) with different chain of lengths allyloxy polyethylene glycol (APEG; either MW 1200 or 2400). The monomers of the cation plus its linker conjugates (APEG(1200/2400)-MPA-N+) were further grafted onto the surface of silicone rubber slides (PDMS) via plasma/UV-induced surface polymerization to form antimicrobial and antifouling coatings. The dual-functional coatings exhibited excellent antimicrobial activities against gram-negative and positive bacteria, and they effectively prevented biofilm formation. The coatings also greatly reduced protein adsorption and platelet adhesion, indicating their excellent antifouling capability. In addition, the APEG(1200/2400)-MPA-N+ cation coatings were biocompatible towards mammalian cells, as shown by in vitro cytotoxicity assays using rabbit erythrocytes and attached human aorta smooth muscle cells. In addition, the APEG(2400)-MPA-N+ coating exhibited significant anti-infective activity in a rodent subcutaneous infection model. We show that the APEG(2400)-MPA-N+ coating is an effective strategy for the prevention of infections associated with indwelling biomedical devices.