Gwynne-James was born at
Pembroke, Pembrokeshire, to Brigadier J Gwynne-James DSO, and later educated at
Cheltenham College. He was regarded as an outstanding cricketer playing in the college's first team for four years and captaining it for two. He also played in the college's rugby team for three years and its hockey team for two. From Cheltenham Gwynne-James attended the
Royal Military Academy Sandhurst and was commissioned as a second lieutenant in the
King's Shropshire Light Infantry (KSLI) on 2 August 1957. He commanded a platoon of the regiment's 1st battalion on active service in the
Mau Mau Uprising and briefly in
Aden during the
Aden Emergency. He was afterwards appointed adjutant of the regiment's depot at Shrewsbury and then of its 4th battalion (
Territorial Army). Gywnne-James was seconded to the Sultanate of
Muscat and Oman, a British protectorate, in 1962. Gwynne-James was promoted to captain on 2 August 1963. He returned to the 1st battalion of the KSLI in 1965 as adjutant in postings at Portsmouth and Singapore. Gywnne-James was given command of the unit's Training Company and then C Company during deployment to Terendak in Malaysia as part of the
28th Commonwealth Infantry Brigade. == Sporting career ==