CONTEXT Although consensus statements and recommendations from professional organizations aim to reduce the incidence of injury or sudden death in sport, nothing is mandated at the high school level. This allows states the freedom to create and implement individual policies. An example of a recommended policy is heat acclimatization. Despite its efficacy in reducing sudden death related to heat stroke, very few states follow the recommended guidelines. OBJECTIVE To retroactively examine why and how 3 states were able to facilitate the successful creation and adoption of heat-acclimatization guidelines. DESIGN Qualitative study. SETTING High school athletic associations in Arkansas, Georgia, and New Jersey. PATIENTS OR OTHER PARTICIPANTS Eight men and 3 women (n = 11; 6 athletic trainers; 2 members of high school athletic associations; 2 parents; 1 physician) participated. Participant recruitment ceased when data saturation was reached. DATA COLLECTION AND ANALYSIS All phone interviews were digitally recorded and transcribed verbatim. A grounded-theory approach guided analysis and multiple analysts and peer review were used to establish credibility. RESULTS Each state had a different catalyst to change (student-athlete death, empirical data, proactivity). Recommendations from national governing bodies guided the policy creation. Once the decision to implement change was made, the states displayed 2 similarities: shared leadership and open communication between medical professionals and members of the high school athletic association helped overcome barriers. CONCLUSIONS The initiating factor that spurred the change varied, yet shared leadership and communication fundamentally allowed for successful adoption of the policy. Our participants were influenced by the recommendations from national governing bodies, which align with the institutional change theory. As more states begin to examine and improve their health and safety policies, this information could serve as a valuable resource for athletic trainers in other states and for future health and safety initiatives.