Harding taught at the University of Pennsylvania, Spelman College, Temple University, Swarthmore College, and Pendle Hill Quaker Center for Study and Contemplation. In the months after King's 1968 assassination, Harding worked with Coretta Scott King to set up the King Center for Nonviolent Social Change in Atlanta, and served as its first director. During those same months in 1968, he worked with a group of scholars to set up Atlanta's Institute of the Black World. He also became senior academic consultant for the PBS television series "Eyes on the Prize".