William Calley is a former United States Army officer who became widely known for his role in the My Lai Massacre during the Vietnam War. In March 1968, Calley and his unit killed hundreds of unarmed Vietnamese civilians, an event that sparked outrage and led to significant controversy regarding military conduct and ethics. In 1971, Calley was court-martialed and found guilty of murder for his actions during the massacre. He was sentenced to life in prison but served only three years under house arrest before his release. The case remains a significant example of the moral complexities faced by soldiers in wartime.