Central Illinois breastfeeding rates fall short of the recommendation to breastfeed exclusively through 6 months, and Black, low-income, and rural families disproportionately experience low rates. A continuity of care framework, which emphasizes interdisciplinary coordination from the prenatal period through weaning, can support breastfeeding. This case study describes an innovative practice model informed by the Collective Impact Model (CIM) designed to promote breastfeeding continuity of care and community support in Central Illinois. Development and maintenance of the Central Illinois Breastfeeding Professional Network (CIBPN), a network of diverse public health practitioners, leveraged CIM principles. The CIBPN began with influential Breastfeeding Champions, identified through the Illinois State Physical Activity and Nutrition program. Champions convened Central Illinois breastfeeding allies and led the CIBPN to coalesce around a common agenda and engage in mutually reinforcing activities. Linked breastfeeding data for families giving birth at a Central Illinois hospital and receiving postnatal care at a health center were analyzed as a snapshot of CIBPN initiatives. The CIBPN engaged at least 135 practitioners and more than 27 organizations. At least 33 people received advanced breastfeeding training, and many professional development opportunities were offered. Numerous breastfeeding support improvements were made at and between CIBPN sites. Breastfeeding rates at the birthing hospital and health center were stable, including during the COVID-19 pandemic. This article contributes to the practice-based evidence for breastfeeding support by strengthening continuity of care through a successful application of the CIM by public health practitioners.