H.E. Maj-General Adu-Amanfoh enrolled at the Ghana Military Academy in 1969. He was commissioned Second Lieutenant in December 1970 and posted to the Army Corps of Engineers.

He had further training at the Royal School of Military Engineering, UK; US Army Engineer School, Fort Belvoir, Virginia; US Army Command and General Staff College, Fort Leavenworth, Kansas, where he was adjudged "Distinguished Allied Officer Graduate;" Unilever Training Centre and Ghana Institute of Management and Public Administration (GIMPA). He was the Honour Graduate of the 1984/85 class of the Ghana Armed Forces Command and Staff College.

Among various other courses at the senior level was training at the Defence Intelligence College, Washington DC. Ambassador Adu-Amanfoh is a Fellow of the International Intelligence Forum.

H.E. Maj-Gen. Adu-Amanfoh held various positions in the Ghana Armed forces, among them Director of Army Training; Lecturer, later Chief Instructor, Army Faculty, Armed Forces Staff College; Director, Army Peacekeeping Operations; Director of Plans and Development, General Headquarters, and Chief of Defence Intelligence.

As a Lieutenant-Colonel, in 1993, he was seconded to the Department of Peacekeeping Operations at UN Headquarters in New York, where he also represented Africa on the pioneer Standby Forces Planning Unit. On his return home he was posted to Army Headquarters to establish the Directorate of Army Peacekeeping and became its first Director, as a Colonel, in 1995.

H.E. Maj-Gen. Adu-Amanfoh's experiences at the UN and at the Directorate of Army Peacekeeping prompted him to write the book - Understanding the UN System and Second Generation Peacekeeping - which is now a standard textbook on peacekeeping in the Armed Forces and at the Security Commission.

He is recognised as the first Ghanaian serving military officer to have authored a book.