First responders place themselves in harm’s way, providing public safety and urgent on-site pre-hospital health care. Their work is physically demanding, requiring 24-hour coverage and ongoing exposure to injury, violence, death and destruction. Rates of post-traumatic stress among first responders ranges from 8 to 32 percent and vary based on the setting, source of the crisis, available support, training, and personal characteristics. Chronic stress and unaddressed trauma can affect first responders’ work performance, relationships, morbidity, and mortality. Traumatic stress can dysregulate neurophysiology and negatively impact psychological and physical health. To remain in the workforce and have a healthy quality of life, it is imperative that first responders are afforded the same psychological support and care that they provide to others. Psychological first aid, support, and cognitive behavioral strategies are among the most promising strategies for fostering resiliency and reducing the impact of stress and PTSD among first responders.