During the first week of a Head Start program in September, Jamal, almost 5 years old, punched another child in the stomach. An assistant looked after the hurt child. Charlane, the teacher, approached Jamal, saying, "There is no hurting children in this class." She marched him to a time-out chair where Jamal sat with his head down. The following Monday Jamal again punched a child in the stomach. Later that day, the teacher asked the home visitor about Jamal. The home visitor had found out that just before the program began, Jamal's mother had been sent to mandatory drug treatment. Jamal and his sisters were split among different relatives. Charlane went out of her way to spend quality time with Jamal during the next few weeks. In the author's view, Jamal was showing reactive aggression. When he punched the other children, his brain told him he was protecting himself. At first, his teacher saw him as a bad child who was misbehaving. She reacted as a technician. To Charlane's credit, with the second conflict she recognized that her technician reaction had not worked. In this moment, she changed from a technician to a "guidance professional", becoming open to understanding and responding to Jamal more constructively. In this article, the author explains the idea behind "technician reaction" and provides tips for handling reaction aggression among troubled students.