We report a protocol for alkene hydroxyalkenylation. Using a persulfate anion as a one‐electron‐oxidation reagent and 1,2‐bis(phenylsulfonyl)ethylene as a radical acceptor in the presence of water, alkenes were converted into the corresponding 1‐phenylsulfonyl‐4‐hydroxyalkenes in good to high yields. The hydroxyalkenylation process involves the nucleophilic hydroxylation of alkene radical cations to give β‐hydroxyalkyl radicals, which, after a radical addition/β‐elimination sequence, provide the products. We also report a photocatalytic protocol for alkoxyalkenylation. A simple protocol for alkene hydroxyalkenylation by 1,2‐bis(phenylsulfonyl)ethylene was developed using persulfate anion as a one‐electron oxidizing reagent. Regioselective hydroxyalkenylation was observed for a variety of substituted alkenes. A photocatalytic protocol for alkoxyalkenylation using an acridinium salt was also successful.