Colonel MacKinlay retired from active duty on 1 October 1998 culminating a 29 year career.  He graduated from the ROTC program at the University of Rhode Island. He also holds a Master of Science Degree from the Florida Institute of Technology, Acquisition and Contracting. He is a graduate of the United States Army War College.

Colonel MacKinlay served in a variety of key assignments throughout his career. His key command assignments include Commander, United States Army, Defense Contract Management Area Office, Defense Contract Management Command, Chicago, Illinois; Commander, Supply & Transportation Battalion, 2^nd Infantry Division, Camp Casey, Korea.

His key staff assignments include Chief, Procurement and Technical Support Division, United States Army, Program and Technical Support, Headquarters Contract Management Command, Cameron Station, Virginia; Quartermaster Branch Colonel’s Assignment Officer, United States Army Personnel Command, Alexandria, Virginia; Chief, Contracts Management Division, United States Army Tank Plant, Warren, Michigan.

Colonel MacKinlay is authorized to wear the Defense Meritorious Service Medal, Legion of Merit, Defense Superior Service Medal, Bronze Star Medal with V Device, Bronze Star Medal, Meritorious Service Medal, Army Commendation Medal. 

Colonel MacKinlay is the recipient of the Distinguished Order of Saint Martin.