Garrison attended Poteet High School in Mesquite, Texas from 1996 to 2000. He played one year at Cedar Valley Junior College in Lancaster, Texas, one year at Kansas Wesleyan University in Salina, Kansas, then finished out with two seasons at Sterling College, graduating in 2004.
In 2002 he was named the All-District Newcomer of the Year and made the KCAC First Team catcher for his season at Wesleyan. In 2003 and 2004 he made the All-District first team as a catcher. In 2003 he was the KCAC Second Team catcher, and returned to the first team in 2004.
2004-2005 Friends University, Wichita, Kansas.
2005-2016 Union High School
2016-2017 Edmond Memorial High School
2017-Present Charles Page High School
Union High School
Garrison came to Union High School in 2005 as the Head Coach on the Junior Varsity team. From 2007-2014 he was the Varsity Assistant Coach and in fall of 2014 he was named the Associate Head Coach.
Union won Regional Championships in 2006, 2007, 2008, 2009, and 2010, with a State Championship in 2010.
Edmond Memorial High School
In July of 2016 Garrison was hired as the Varsity Head Coach at Edmond Memorial High School, replacing Kyle Roberts.
Charles Page High School
Garrison was hired as the Varsity Head Coach in Sand Springs for the 2017-2018 season, replacing longtime Head Coach Bill Hutson.
2016-2017 Edmond Memorial (14-19)
2017-2017 Charles Page
Assistant Coach (280-145)
2004-2005 Friends University (17-11)
2005-2006 Union High (29-12)
2006-2007 Union High (25-6)
2007-2008 Union High (21-14)
2008-2009 Union High (27-10)
2009-2010 Union High (30-10)
2010-2011 Union High (18-18)
2011-2012 Union High (24-15)
2012-2013 Union High (24-8)
2013-2014 Union High (19-17)
2014-2015 Union High (25-12)
2015-2016 Union High (21-12)