Coyne began his career with the Department of Corrections as an officer at Luther Luckett Correctional Complex (LLCC) in February 1999. He was promoted to sergeant in May 2000 and remained at LLCC. In August 2001, he was promoted to Lieutenant and transferred to the Roederer Correctional Complex (RCC). Coyne later transferred to the RCC Assessment Center as a classification and treatment officer. Coyne was subsequently promoted to captain, unit administrator I and unit administrator II all while serving at RCC.
Coyne served three years of active duty and 17 years in the Kentucky Army National Guard, where he was twice deployed overseas for Operation Iraqi Freedom. He attained the rank of first sergeant before retiring from the military.
Coyne is a graduate of the University of Louisville where he earned a Bachelor's degree in Justice Administration.