Introduction This study aimed to describe Maternal Child and Family Health Nurses’ (MCaFHNs) perception of their role across Australia. MCaFHNs deliver services to positively influence the growth and development of children in the early years. Little is known about their role as they deliver care to children and families in Australia. Methods This study used in-depth qualitative inquiry. Sixteen expert MCaFHNs from the eight jurisdictions in Australia took part in semi-structured interviews conducted from April 2013 to August 2013. The data were transcribed verbatim, validated by participants, and analysed thematically. Results The results indicated that the MCaFHNs’ role is embedded in the principles of primary health care under an umbrella of universal service delivery with increasing overall complexity. Health promotion and early intervention are key components of the role, with services focused heavily on child growth and development and maternal mental health. Delivery of services by MCaFHNs was enriched by specific approaches to care, such as working in partnership with families, and all aspects of the role were enabled by essential specialist skills and knowledge. Discussion While role descriptors, educational backgrounds and experiences vary, participants overwhelmingly report similarities in practice. This study identified tangible reasons for the development of a nationally consistent role and practice in Australia, enabling consistency and equity of best models of practice. Such a description is essential to enable transferability and comparison with nurses working in similar contexts internationally.