His father, John (Jack) Truman Carter Jr. (Michael Gross) is caring but stiff, and very acquiescent with his wife until he gets tired of her being an "emotional vampire '' and divorces her. He and Carter have an awkward relationship where they love each other but John does n't respect his father. Jack recognizes this and keeps some distance from him as a result of it. Carter 's mother, Eleanor (Mary McDonnell), is emotionally distant and cold. Her personality was largely shaped because she blamed herself for Carter 's older brother, Robert 's death from leukemia. Carter eventually figures out that much of her sadness comes from this and they briefly become closer, but eventually Eleanor removes herself from any ties to her family after Jack divorces her, to the point where John has no idea how to reach her and she refuses to return a phone call he makes after Millicent Carter (who hated her) passes away.
who played john carter's mother on er
Mary McDonnell