He joined the Gambian National Army and was commissioned as a second lieutenant on 29 September 1989, serving as the officer in charge (OIC) of the Presidential Escort, part of the Presidential Guards, from 1989 to 1990. In 1991, he served as the officer commanding (OC) the Mobile Gendarmerie, and from 1992 to 1994 was the OC of the Gambia National Army Military Police. On 1 February 1992, he had been promoted to lieutenant. Jammeh was the head of security detail attached to Pope John Paul II during his visit to the Gambia in February 1992. He attended the Military Police Officers Basic Course (MPOBC) at Fort McClellan in the United States from September 1993 to January 1994.