While patient safety focuses on the role systems play in poor patient outcomes, an ongoing dialogue exists about how health care should address and hold accountable individual bad providers. This case control study demonstrated a strong association between physicians with documented unprofessional behavior in medical school and subsequent disciplinary actions from a state medical board. Unprofessional behavior included severe irresponsibility and diminished capacity for self-improvement. Overall, the authors estimate for the population that nearly a quarter of individual physicians involved in disciplinary action can be predicted in medical school based on these behavioral observations. Professional behavior should continue to demand adequate attention in medical school and postgraduate training, as its presence seems to sustain over decades.