School entry provides an opportune moment for health professionals to intervene with children who are overweight, yet identification and management of childhood obesity presents challenges in practice. This multi-method qualitative study explored the experiences of 26 school health professionals in addressing childhood obesity at school entry. Methods included semi-structured interviews with service managers (n = 3); focus groups with school nurses (n = 12) and child health practitioners (n = 6); and open-ended questionnaires with school nurses (n = 4) and child health practitioners (n = 1) who were unable to attend the focus groups. A thematic analysis revealed agreement between service managers, school nurses and child health practitioners. Whilst it was felt school health professionals have an important role to play in managing childhood obesity, efforts to address child weight were limited by a lack of capacity, lack of clear protocols, challenges of engaging parents and insufficient training in childhood obesity and related lifestyle issues. School health policymakers need to recognize childhood obesity as a serious public health issue, allocate appropriate resources to nurse training and development and ensure clear pathways are established to ensure consistency of care.