In response to (a) an increasing need to support children with emotional and behavioral challenges in childcare settings and (b) the high rates of expulsion among preschool children, mental health consultation in early childhood settings is becoming an increasingly popular intervention strategy. At the same time, there is little agreement or empirical evidence to help early childhood program managers and other professionals make decisions about the most important characteristics and services that mental health consultants should provide. The current study presents findings from a nationally representative survey of 74 Head Start programs and 655 Head Start directors, staff members, and mental health consultants to use in addressing this gap. Using Hierarchical Linear Modeling (HLM), the authors present results suggesting that the single most important characteristic of mental health consultants is their ability to build positive collaborative relationships with program staff members. The frequency of consultant activities was important, primarily because consultants who provided more frequent services were reported to have more positive relationships with staff members. These results were significant even after controlling for program-level characteristics, such as program size, budget for mental health services, and ratio of consultant hours to number of children.