In the polymeric title compound, [K(C(15)H(9)O(7)S)](n), the potassium cation is five-coordinated by four sulfonate O atoms and one carbonyl O atom. Two intra-molecular O-H⋯O hydrogen bonds stabilize the conformation of the anion. The polymeric three-dimensional supra-molecular architecture is formed via coordination inter-actions and π-π stacking inter-actions involving centrosymmetrically related pyrone rings, with a centroid-centroid separation of 3.513 (2) Å.