Sulfonyl fluorides are versatile functional functional groups that can participate in SuFEx "click chemistry". We have developed several new methods to synthesise sulfonyl fluoride-containing polymers via alternating copolymerisation of ethylenesulfonyl fluoride with styrene, and via C-H functionalisation of polyethylene glycol. These polymers have been applied in the synthesis of biocompatible hydrogels, pH and metal sensors, drug conjugates and solid-state battery electrolytes, demonstrating the broad utility of these new materials.