Oxindoles are important scaffolds in medicinal chemistry, found in many natural products and drugs. We present a new visible-light-driven method for synthesizing oxindoles via intramolecular radical cyclization. This mild and sustainable approach uses decarboxylation of carboxylic acids to generate carbamoyl radicals that enable ring closure. The reaction shows broad functional group tolerance, allowing diverse modifications on both the olefin and amine component. This method enhances structural diversification of oxindoles and expands photochemistry’s role in heterocycle synthesis for drug discovery.