Over the last decade, fitness industry registers have become a global phenomenon. This interpretative research focuses on how 12 New Zealand fitness centre managers perceive affiliation/non-affiliation with a fitness industry register. Representatives from the New Zealand Register of Exercise Professionals (REPs NZ) and Fitness New Zealand also contributed. Findings lend further support that organisations are both strategically and institutionally motivated to affiliate to incur legitimacy. Network legitimacy is crucial as it encourages field buy-in and federation dependencies via three critical components: network administrative organisation (NAO) legitimacy, institutional structure, and affiliate legitimacy. Supervised by Dr Sean Phelps (Senior Lecturer AUT New Zealand) who has extensive experience with major United States sport events and several Olympic Games. Additionally, supervisor Dr Nico Schulenkorf (Lecturer UTS Australia) has been instrumental in sport-for-development and health promotion in Sri Lanka, Israel and the Pacific Islands. This research further assists in identifying “how” and “why” federation affiliates and their wider community perceive “what” is important.