Background: Caring for older people has become a focus for simulation-based education. Specifically, aging simulation has emerged as an innovative and effective educational approach that utilizes aging-suits for nurses to gain insight into the aging process and the everyday difficulties faced by older people. There is limited evidence within the literature about how researchers and educators support decision-making processes in the design, implementation, and evaluation of aging simulation programs. Aim: This is a theoretical development paper and its purpose is to explore the practical application of the Jeffries Simulation Theory in the design, implementation, and evaluation of an aging simulation program to contribute to knowledge development and guide educational practices for nurse educators and researchers. Results: The authors describe a practical application of the theory to an aging simulation program using the five key theory components: context, background, design, simulation experience, and outcomes. Specific theory strengths are highlighted in practical examples generated from the authors aging simulation interventional study example: engaging stakeholders, consideration of additional observer simulation roles, reflective debrief discussions, influence of facilitator and participant personal attributes, and outcomes beyond the participants. Conclusion: The Jeffries Simulation Theory is well suited for underpinning the design, implementation, and evaluation of aging simulation programs.