Fairness and due process in the criminal justice system are all but unattainable without effective legal representation of indigent defendants, yet we know little about attorneys who do this critical work—public defenders. Using semi-structured interviews, this study investigated occupational stress in a sample of 87 public defenders across the United States. We show how the intense and varied chronic stressors experienced at work originate in what we define as the stress of injustice: the social and psychological demands of working in a punitive system with laws and practices that target and punish those who are the most disadvantaged. Our findings are centered around three shifts in American criminal justice that manifest in the stress of injustice: penal excess, divestment in indigent defense, and the criminalization of mental illness. Working within these structural constraints makes public defenders highly vulnerable to chronic stress and can have profound implications for their ability to safeguard the rights of poor defendants.