In February 1964 he received a commission into the
British Army's
Royal Leicestershire Regiment, which was amalgamated into
The Royal Anglian Regiment seven months later. He joined the
Parachute Regiment in 1972, and was promoted to
major serving with 10 Para in 1975. On 28–29 May 1982, at the
Battle of Goose Green during the
Falklands War, Keeble assumed command of the 2nd Battalion of
The Parachute Regiment (2 PARA) after its commanding officer, Lieutenant-Colonel
H. Jones, had been killed in action. A devout
Christian, Keeble, then a
major, took over the leadership of the battalion at a point when its attack upon the
Argentine Army position had broken down, having lost 16% of its strength as casualties; it was short of ammunition, had been without sleep for 40 hours, and was in a debilitated condition to face the unknown potential of a counter-attack from the Argentine forces present in the vicinity. After kneeling alone in prayer amongst the burning gorse seeking guidance as to what to do, Keeble conceived the idea of refraining from more attacks to try a psychological ploy, subsequently releasing several captured Argentine prisoners of war in the direction of their Goose Green garrison, carrying messages into it requiring its surrender or threatening it with a fictitious large-scale assault by the British forces, supported by artillery. The Argentine commander, Lieutenant Colonel
Ítalo Piaggi, subsequently surrendered the garrison to the Parachute Regiment without further fighting. After the battle, despite popular sentiment among the soldiers of 2 PARA for him to remain in command, he was replaced by Lt. Col. David Chaundler, who was flown in from the United Kingdom to take command of the battalion. At the end of the conflict Keeble was decorated with the
Distinguished Service Order. He then commanded
15th Bn Parachute Regiment, a Territorial Army battalion based in
Scotland, with its HQ in
Glasgow. Keeble finished his military career with the rank of lieutenant colonel on 27 September 1987, his final appointment having been a staff officer grade 1 at
Allied Forces Central Europe in the
Netherlands. ==Post-military life==