Multidisciplinary intervention approaches are needed for meeting service needs for families in which substance abuse and mental health disorders may be interfering with child‐rearing. Experiences from the Starting Early Starting Smart (SESS) initiative, a 12‐site national collaborative investigation of integrating behavioural health services in early childhood and primary health care service settings for children aged 0–5 years and their families and caregivers, are described. This 4‐year applied research initiative was co‐funded by the Substance Abuse and Mental Health Services Administration of the US Department of Health and Human Services and Casey Family Programs, a private operating foundation. SESS, which was developed and implemented in 12 geographically and culturally diverse cities in the USA during 1997–2001, encouraged federal, state, and local public/private partnerships. Opportunities and challenges in using an inclusive, consensus‐based, stakeholder model to maximize study relevance and utility for researchers, practitioners, and fiscal sponsors are discussed, and lessons for multidisciplinary, multisite research collaborations are identified.