This qualitative study used the Consolidated Framework for Implementation Research (CFIR) to systematically identify the barriers and facilitators to implementing the Healthy Eating Research Nutrition Guidelines for the Charitable Food System (HER Guidelines) in a national sample of U.S. food banks. In-depth interviews were conducted among a random sample of food banks that reported implementing the HER Guidelines for at least 1 year. Interviews (12 food banks) were recorded and transcribed. Food banks employed different approaches to implementing the HER Guidelines yet often faced similar successes and challenges. Successful HER implementation practices included strategies to prioritize resources, such as focusing efforts on purchased items first and using online tools like WellSCAN to rank foods from USDA (US Department of Agriculture) food programs. Challenges included difficulties evaluating the categories of mixed dishes and grains, evaluating assortments of donated foods, and having enough staff to complete the task of ranking. Food banks expressed the need for more educational resources to train food bank staff members involved in the implementation of the HER Guidelines. This study identified successful strategies, common challenges, and opportunities to improve the implementation of HER Guidelines to support the availability of healthier food products across the charitable food system.