Cooper was commissioned on a short service commission as a Chaplain to the Forces, Fourth Class, on 20 March 1973. On 20 March 1979 he switched to a full commission and was promoted to Chaplain to the Forces, Third Class. He was appointed chaplain to 2 PARA in late 1980, and so accompanied the battalion to the
Falkland Islands in 1982 when the battalion, with
3 PARA, was attached to
3 Commando Brigade to bring that unit to full wartime strength. During the Battle of Goose Green he was attached to the
Regimental Aid Post, comforting the wounded, and assisting in the organisation of their evacuation. Following the battle he conducted a field burial service, film of which was later shown on television news programmes. He was also present when the battalion was shaken by an ammunition explosion in the aftermath of Goose Green, and during the
Battle of Wireless Ridge. At the conclusion of the campaign he was recommended for a
Military Cross by the new CO of 2 PARA, Lt-Col David Chaundler; this was endorsed by the brigade commander,
Brigadier Julian Thompson who "Very Strongly Recommended" the award, and the divisional commander,
Major General Jeremy Moore, who "Strongly Recommended" it; but
Lieutenant General Sir Richard Trant downgraded the award, instead "Very Strongly Recommend[ing]" a
Mention in Despatches, and this was endorsed in similar terms by
Admiral Sir John Fieldhouse. Chaundler's recommendation closed with the words "The Battalion owes an enormous debt of gratitude to a selfless, dedicated and courageous man who lives up to the very highest traditions of his calling." The Mention was
gazetted on 8 October 1982. ==Eton College==