Throughout the history of the NFL, several head coaches have found significantly more success than their peers. The purpose of this paper is to provide a better understanding of what personal and tactical dimensions have set these coaches apart. This paper will study the most successful coaches of the past, as well as today’s most successful coach, Bill Belichick. Through case studies, this paper identifies possible explanation for Belichick’s current run of success in an NFL that grows more competitive each season. Specifically, this paper looks at the relationship between players and coaches, and how Leader- Member exchange plays a very important role in the success coaches will find. Leader- member exchange (LMX) has not been studied in the NFL, and this paper predicts that future research in this area will find the most important factors of LMX to be trust, respect, and predictability of actions. This paper also looks at the role of the head coach outside of his player relationships, and how vast football knowledge is not enough to lead an NFL team to success. Head coaches that are most successful differentiate themselves from others through the tactical side of the game, in many different aspects, including player acquisition, game preparation and tactics, personnel management and decision- making. Last, this paper examines the coaching career of Bill Belichick, and why he has found immense success in the NFL. Further research in the field of player-coach relationships would provide a clearer answer for successful coaches in the NFL.