Advanced fluorinated proton‐conducting membrane are dominating functional macromolecules due to their high performance in electrochemical energy devices. However, the co‐ion leakage and low power densities still proposes a challenge. Herein, a novel functionally tailored polyvinylidene fluoride‐ co ‐(γ)‐sulfopropyl acrylate (PVDF‐ g ‐SA) based proton‐conducting membrane is prepared for vanadium redox flow batteries (VRFBs). The approach introduces a facile guideline to design halato‐telechelic −SO 3 H architectures by tethering γ‐sulfopropyl acrylate onto dehydrofluorinated PVDF. The optimized PVDF‐ g ‐SA‐15 exhibits proton conductivity (κ m H+ ) of 17 mS cm −1 ( akin Nafion: ~19 mS cm −1 ) and retained 87 % and >95 % of its properties in Fenton's reagent and 3 M H 2 SO 4 , respectively. In VRFB device, the PVDF‐ g ‐SA‐15 shows ∼98 % capacity utilization outperforming Nafion‐117 (∼85 %). Moreover, bearing dense ionic orientation ( viz AFM phases), the potential drop rate is ~2× lower for PVDF‐ g ‐SA‐15 (1.4×10 −3 V min −1 ) than that of Nafion‐117 (2.6×10 −3 V min −1 ). Operational endurance is evaluated fit for 150 mA cm −2 showing maximum coulombic, energy and voltage efficiencies of >98 %, ∼78 %, ∼80 %, respectively. Further investigation for ~200 cycles infer excellent durability with ∼95 % property retention. Additionally, the PVDF‐ g ‐SA‐15 can deliver ~20 % higher power density than Nafion‐117 does. Thus, the revealed alternate membrane holds promising utility in VRFB applications.