He was born in Rossville, Georgia, United States, to Robert L. Coffey, a brick manufacturer and Curie Ethel Brindley, a milliner.
After the failure of his business during the Great Depression, Robert Coffey, Sr. moved the family first to Philadelphia and finally to Johnstown, Pennsylvania, where he found work as supervisor in a coal mine.
In 1948 he left active service, and returned to the United States, and while still in the Military Reserves, enrolled in the University of Miami on the GI Bill.
While in Mainz his skills as a community liaison prompted an invitation for him to join the Reitercorps of the Mainzer Ranzengarde, a local equestrian club, an honor normally reserved for Germans.
He created an operational planning concept covering all aspects of conventional warfare that became a basic reference for the work of the USAFE Force Employment Panel on which Lt. Col. Coffey was assistant chairman and coordinator.
He also played a prominent role in the movement to preserve public access for Fisheating Creek when private interests threatened to abolish it.