Trennis has been a high school English teacher, pastor, chaplain, and crisis counselor.

Over the past twenty years, he has counseled hundreds of people for many different relationship problems and addictions including over five-hundred suicidal individuals. As a police chaplain, he has also been on scenes and otherwise involved with many completed suicides.

He has also observed the leadership styles of many first-level supervisors in various first responder agencies. From this exposure came the motivation for his first responder series. He saw a need for occupational specific training in leadership and other relationship areas for all first responders.

He has always been an avid student of the Bible, always spending as much time as possible in the original Greek and Hebrew.

He and his wife, Ann, live in Cottonwood, Arizona, where he writes, counsels, and serves as a chaplain for the Arizona Department of Public Safety and the Cottonwood Police Department.