In 1919, Gross started his career as an assistant professor of chemistry (1919-1920) at
Duke University. Gross was quickly promoted to full professor and served as chair of the chemistry department from 1921 to 1948. In 1947, Gross became the Dean of the Graduate School (1947-1952), Dean of the University (1952-1958), and Vice-President in the Educational Division (1949-1960). Gross' opinions on administrative matters led around 1960 to conflicts with President
A. Hollis Edens in what came to be known as the Gross-Edens Affair. The debate was mostly over whether Duke University should become a regional or national university, and to what degree the institution should be known for its devotion to research or teaching. Gross pressed for rapid growth towards national stature as a research university, an outcome that Duke did later achieve. Edens resigned from his position as University President, and Gross was removed from his administrative position as a result of the conflict. Gross was a founder of the Oak Ridge Institute for Nuclear Studies (later
Oak Ridge Associated Universities) and served as its President until 1949. President Harry S. Truman appointed Gross to the original
National Science Foundation board in 1950, a position he held for 12 years. Gross served as
President of the American Association for the Advancement of Science in 1962. == Awards and honors ==