Knight was one of the world's leading economists, having made significant contributions to many problems of both economic theory and social philosophy. He is best known for his Risk Uncertainty and Profit, a monumental study of the role of the entrepreneur in economic life. In 1950 he was president of the American Economic Association and in 1957 the recipient of its coveted Francis A. Walker Award, given "not more frequently than once every five years to the living (American) economist who in the judgment of the awarding body has during his career made the greatest contribution to economics."