Hydration is central to mitigating surface fouling by oil and microorganisms. Immobilization of hydrophilic polymers on surfaces promotes retention of water and a reduction of direct interactions with potential foulants. While conventional surface modification techniques are surface-specific, mussel-inspired adhesives based on dopamine effectively coat many types of surfaces and thus hold potential as a universal solution to surface modification. Here, a facile, one-step surface modification strategy is described that affords hydrophilic, and underwater superoleophobic, coatings by the simultaneous deposition of polydopamine (PDA) with poly(methacryloyloxyethyl phosphorylcholine) (polyMPC). The resultant composite coating features enhanced hydrophilicity (i.e.; water contact angle of ≈10° in air) and antifouling performance relative to PDA coatings. PolyMPC affords control over coating thickness and surface roughness and results in a nearly tenfold reduction in Escherichia coli adhesion relative to unmodified glass. The substrate-independent nature of PDA coatings further promotes facile surface modification without tedious surface pretreatment and offers a robust template for codepositing polyMPC to enhance biocompatibility, hydrophilicity, and fouling resistance. An antifouling composite coating is prepared by one-step simultaneous deposition of a polymer zwitterion with the surface-adherent polydopamine. The facile incorporation of poly(2-methacryloyloxyethyl phosphorylcholine) (polyMPC) into these coatings reduces Escherichia coli adhesion by nearly tenfold relative to polydopamine and glass control samples.