He remained in Louisville for sixteen years, except for a year spent on the faculty of the University of the City of New York. With Drake and his colleagues, Gross helped make the Louisville Medical Institute the most important medical center in the western United States. During Gross's time there, the institution attained a reputation equal to similar ones east of the Appalachian Mountains, and at the time of Gross's hiring, his fellow professors at Louisville had all attained national if not international fame in their respective fields.