Aim: Changing population demographics, service demands, and healthcare provider expectations suggest that a shift is required regarding how malnutrition care is managed in hospitals. The present study aims to build the reason for required change, and to describe the process used to develop a model for managing malnutrition for implementation across six Queensland hospitals. Methods: A cross-sectional survey of approaches to managing malnutrition in Queensland public hospitals, and development of a new model of care (guided by Knowledge-to-Action Framework and qualitative interviews) for testing within a broader implementation program. Results: Twenty-three surveys were distributed with 21 completed by metropolitan (n = 11), regional (n = 8), and rural/remote (n = 2) settings. Substantial within and across site variance was observed, with care processes focused towards highly individualised, dietitian delivered care. Some early adopter sites demonstrated systematic, interdisciplinary or delegated malnutrition care processes; however, the latter was rarely or never undertaken in eight sites. A model for the Systematised, Interdisciplinary Malnutrition Pathway for impLementation and Evaluation (SIMPLE) in hospitals was drafted based on identified contemporary models and supporting literature. A mixed-methods approach combined survey data with structured interviews conducted in six sites, purposively sampled for maximal variation to iteratively refine the model. Consensus for implementation of the final model was achieved across site clinicians, leaders, and governance structures. Conclusions: Systematised, delegated, and interdisciplinary nutrition care activities are realistic in at least some settings. A model is now available to provide interdisciplinary care. Next steps including testing implementation will determine if this interdisciplinary model improves malnutrition care delivered in hospitals.