As Chairman of the Department of Surgery at the University of Arizona, Gruessner oversaw the surgical management for the victims of the 2011 Tucson shooting. The patients included former US Congresswoman Gabby Giffords, who suffered a critical gunshot wound to the head. While in Arizona, Gruessner performed the state's first living and deceased intestinal transplants, first multivisceral transplant, first pediatric living donor liver transplant and first autologous islet transplant.