Infants most vulnerable to trauma are often the least able to access interventions. Universal child-serving systems, such as primary pediatrics, early care and education, and the child welfare system, can offer a port of entry for millions of children annually for trauma-related supports and services. However, practitioners in these systems have varying levels of professional training and often express discomfort in exploring this topic with families. The co-location of infant mental health clinicians in these systems builds capacity to identify and treat trauma-affected children and builds competencies in extensive networks of professionals. This article describes a range of successful services and supports in these systems.