Upon completing his basic training in Hong Kong, he joined the 2nd King Edward VII Gurkha Rifles (2GR) in November 1993 (later The First Battalion, The Royal Gurkha Rifles (1 RGR)). After his Junior Leadership Cadre, he completed ‘P’ Company and jump course in 1998 and joined the Recce Platoon in 1 RGR.

As a Senior Non-Commissioned Officer, he had taken numerous appointments, including instructor at Close Observation Training and Advisor Team (COTAT), the First Gurkha Instructor in this environment. He also took the Company Quartermasters appointment and Instructor at Jungle Warfare School in Brunei. On promotion to Warrant Officer Class Two, he was then posted to 1 Mercian Regiment as the Company Sergeant Major G (TOBRUK) Company and deployed on Operation HERRICK 12.

Major Gyan was commissioned in July 2011 and took on roles as Platoon Commander and Company Second in Command of (C Mogaung Company in 1 RGR and Gurkha Company Catterick, respectively). During his tenure as the Second in Command of Gurkha Company Catterick, Major Gyan made a significant impact by implementing a cashless policy. This initiative aimed to safeguard vulnerable recruits and staff while ensuring that the quality and quantity of service remained uncompromised.

On promotion to the rank of Major, he assumed command of the Headquarters Company at the Infantry Training Centre, Catterick (Support Battalion) in April 2017. This marked an historic milestone as he became the first Gurkha Officer Commanding (OC) in a British Battalion. After serving 1.5 years as the OC Headquarters, under his leadership and initiative the Training Support (BABAJI) Company was established on the 19th of September 2018. After completing over four years of Sub-Unit command appointments, he became the first Gurkha Officer to serve as a Staff Officer Level Two within a diverse multi-national and Tri-Service Headquarters.

Major Gyan’s operational experiences include serving on Operation AGRICOLA – KOSOVO (1999), Operation SILKMAN – Sierra Leone (2001), Bosnia (2003/2005 – In a Static Covert Surveillance role) and Operation HERRICK 12 and 17.