Garrett graduated from Littlefield High School and then went on to play baseball at Wayland Baptist University.

After graduating from Wayland Baptist in 1999, Garrett began his coaching career in his hometown of Littlefield. After 3 years in Littlefield, he was hired as the Head Baseball Coach in Lockney. While in Lockney, he took his team to the Regional Finals in 2007. In 2008, he accepted a coaching position in Idalou. While in Idalou, he was a part of the 2009 Football and Basketball State Championship teams. It was the first ever 2A pragram to win both the football and basketball state championship in the same year. In 2014, as the Head Baseball Coach at Idalou, Garrett's team finished as the State Semifinalists.  It was the first ever school appearance at the State Tournament in baseball, and Garrett was also selected as a THSBCA All-Star Coach.

Coach Heard has led and facilitated FCA Huddles for the last 18 years starting in Lockney. In 2008, he served at the Texas A&M FCA Sports Camp as a baseball coach. Since 2013,  he has also served as the Head Baseball Coach at the Texas Tech FCA Sports Camp. After 21 years of coaching,  Coach Heard accepted an Ambassador position with the South Plains FCA in 2020.

Garrett is married to April Heard and they have three children: Bo (17), Logan (15), and Jude (10). They are members of First Baptist Church Roosevelt where Garrett currently teaches the 5th/6th grade Sunday School class, leads the Men's Ministry, and has recently been ordained as a Deacon.