Carter's grandfather, John Truman Carter Sr. (George Plimpton), is the most disappointed by Carter's career choice, and though Carter respects him, he also resents him for that. Carter's grandmother, Millicent Carter (Frances Sternhagen), is a benefactor of the hospital, even funding Carol Hathaway's clinic. Carter is very close to his grandmother (whom he calls "Gamma") and intermittently lives at her home. They do occasionally argue, however, usually in regard to Carter's reluctance to participate in matters related to the family foundation; Gamma modifies her will to remove Jack as the head of the foundation and puts John in charge of it, leading to him changing its mission from supporting Chicago arts programs to supporting public health initiatives.