Nutrition and feeding interventions are important for children’s growth and development. Holt International’s Child Nutrition Program (CNP) is a child nutrition and feeding intervention. This study aims to describe and explore the implementation of CNP in Mongolia and the Philippines using mixed methods including qualitative and quantitative data analysis. The analysis framework was guided by the WHO’s Monitoring the Building Blocks of Health Systems. Key informant interviews (KIIs) were conducted, transcribed, translated and coded. Knowledge, Attitude and Practice Surveys (KAPS) and pre-/post-tests from routine program audit data were analyzed. Analysis of nutrition (Mongolia: 95% CI: 7.5-16.6 (p = < 0.0001), Philippines: 95% CI: 7.6-15.7 (p= < 0.0001)) and feeding (Mongolia: 95% CI: 11.7-23.9 (p = < 0.0001), Philippines: 95% CI: 6.6-16.9 (p = < 0.0001)) tests indicate improvement post-training in both countries. KAPS indicate changes in desired practices from pre-training to post-training. Thematic analysis of KIIs highlight essential components for program implementation and effectiveness, including strong leadership, buy-in, secure funding, reliable supply chains, training and adequate staffing. This evaluation of program implementation highlights successful strategies and challenges in implementing CNP to improve the health of children in Mongolia and the Philippines. Lessons learned from the implementation of CNP can inform growth of the program, scaling strategies and provide insights for similar interventions.