Context: As athletic training continues to evolve as a profession, several epistemological considerations must be considered. These include how we generate professional knowledge and how we secure and legitimize it in both professional and public spheres. Objective: The purpose of this commentary is to provide an overview of how athletic training has defined its body of knowledge. By contrasting our professional knowledge with recent advancements in medical cognition and epistemology, we aim to provide a more robust definition of professional knowledge for our profession. Background: A profession is defined as an occupation that has a unique knowledge base and skill set that, when wielded, fulfills an ethically founded social contract with the public. One of the greatest challenges for the profession of athletic training as we move into the future is securing a knowledge base that is uniquely our own. Synthesis: In this commentary, we synthesize the process by which we secure our body of knowledge through the Role Delineation Study with emerging trends on the nature of professional knowledge from the medical and health care literature. Results: Based on the evidence presented, we propose a new definition for professional knowledge in the context of athletic training: "Information that is purposefully linked together to develop the ability to explain and predict the clinical phenomena associated with the profession's social contract." Recommendation(s): As this new epistemological definition holds the potential to better structure and guide the athletic training's professional transformation, including its professional education processes, we recommend this model be considered for adoption and implementation. Conclusion(s): It is apparent that a new construct for professional knowledge, one capable of supporting the profession's infrastructure and intentions, is needed for athletic training. In addition, and crucial to the formation of our professional body's construction of knowledge, is a need for collecting multivariable outcomes concerning our ability to legitimize it.