Knox returned to Edinburgh by Christmas 1822. On 1 December 1823 he was elected a Fellow of the Royal Society of Edinburgh. During these years he communicated a number of well-received papers to the Royal and Wernerian societies of Edinburgh on zoological subjects. Soon after his election he submitted a plan to the Royal College of Surgeons of Edinburgh for a Museum of Comparative Anatomy, which was accepted, and on 13 January 1825 he was appointed curator of the museum with a salary of £100.