In Philadelphia Gross became one of the most prominent members of several medical organizations as physicians in the United States increasingly sought to professionalize their vocation. He served as the twentieth president of the American Medical Association (AMA), and delivered the presidential address at the 1868 session, where the first item on the agenda was to more efficiently publish and create a more scholarly and scientific focus for the "Transactions of the American Medical Association", the forerunner of the "Journal of the American Medical Association". During his time in Philadelphia Gross also helped found the American Surgical Association and the Philadelphia Pathological Association. Earlier in Kentucky he had founded, with T.G. Richardson, the "Louisville Medical Review" and the "North American Chirurgical Review".