This chapter examines Dugald Stewart’s (1751–1828) efforts to reform, defend, and sustain the legacy of Scottish common sense philosophy throughout his professional life. The first section discusses Stewart’s enrichment of Reid’s philosophy by developing a modern program of moral education that encouraged scientific innovation during an age of revolutionary change. This campaign to preserve Scottish Enlightenment intellectual and religious culture from modern philosophical skepticism encountered competition at the end of Stewart’s career. Section two turns to Stewart on the endurance of Scottish common sense philosophy in response to the early nineteenth-century Scottish reception of German Idealism and the rise of Scottish Romanticism at Edinburgh University. Considered by many to be the “Scotian Plato,” Scottish common sense philosophy flourished under the care of Dugald Stewart during two of the most transitional moments in the final decades of the Scottish Enlightenment before its displacement in late nineteenth-century Scotland.