Brennan grew up in North West Tennessee and fell in love with the game of basketball at an early age. He graduated from the University of Tennessee at Martin and began his career as a teacher and coach. After a year coaching at the middle school level, Brennan began working as a coach at Dyer County High School for 3 years. He served as an assistant varsity coach, head JV coach, and head freshmen coach. As a high school assistant coach in Tennessee, Brennan was a part of the 2012-2013 AAA State runner up team, which included the 11th ranked high school player in the country, 5 star guard Robert Hubbs (University of Tennessee).
Brennan is currently serving as the head JV coach at Southern Lee High School in Sanford, NC. He enjoys teaching the game of basketball, positively impacting the lives of players, and developing good relationships with players and coaches.