Aim. The aim of this article is to report the process and outcomes of codesigning a nursing leadership program for fundamental care. The leadership program is designed to empower nursing leaders, across research, education, clinical practice, and policy, to challenge and change how fundamental care is valued, prioritised, and actioned within health and care systems. Background. Deficits in fundamental care represent an intractable problem adversely impacting care recipients, care providers, and health and care systems globally. These deficits stem from the minimal value placed on fundamental care and its subsequent invisibility across research, education, clinical practice, and policy. Sustainable systems change requires effective nursing leadership; however, existing nursing leadership programs tend to address only one area of health and care systems, typically clinical practice, and do not focus specifically on fundamental care. Methods. The Fundamentals of Care Leadership Program was codesigned with current and emerging nursing leaders using a participatory action research approach. The collaborative codesign process involved two stages: (1) idea generation and preliminary program development via Nominal Group Technique (n = 60 participants from 11 countries) and (2) refinement and trialling of program content and process via a three-day workshop (n = 19 participants from 9 countries). Results. Participants prioritised a program that provided clear understanding of the concept of fundamental care, enabled the development of influencing and negotiating skills to advocate for this care, and offered resources on knowledge translation, implementation, and measurement strategies. Participants also wanted allotted time to design research and quality improvement projects that would allow them to transfer the skills learned to the real-world issues occurring within their respective organisations. Conclusions. The codesign process, embedded within a participatory action approach, enabled the development of a Fundamentals of Care Leadership Program that is shaped by, and meets the needs of, current and emerging nursing leaders. The leadership program will enable nursing leaders to challenge value systems on fundamental care and to champion this care across research, education, clinical practice, and policy, working towards enhanced fundamental care outcomes and experiences.