John Christmas Møller was born on 7 October 1924, as the only child of the Danish Foreign minister conservative John Christmas Møller (1894-1948).

John received his education at Herlufsholm boarding school, but on 9 April 1940, when Denmark was occupied, he was a student at the English boarding school Bromsgrove near Birmingham.

The trip home to Denmark therefore had to take place via neutral Portugal, but in November 1940 he was again a student at Herlufsholm.

As the occupation period in Denmark progressed, John's father came more and more on a collision course with the German occupation authorities, who in January 1941 insisted that the Danish politician had to leave all his political posts.

As a result, plans were made for an escape to England with the whole family. With notification to Herlufsholm that John was ill at home, the Christmas Møller family was shipped out from Aggersund in Jutland on 30 April 1942 and sailed to Sweden, from where they were flown to Scotland shortly afterwards.

While Christmas Møller senior continued his political work in the "Danish Council" immediately after his arrival in England, John tried to sign up for service in the British army, but was initially rejected as he was not yet 18 years old.

He did not give up, however, and on 19 March 1943, after several rejections, he succeeded in being accepted as an officer cadet in the distinguished guard regiment The Grenadier Guards.

Although his poor academic skills once again gave him problems, he managed to complete recruit training and the subsequent officer training at the British officer school Sandhurst.

Shortly before his 19th birthday, a proud father and mother were able to witness his appointment as Second Lieutenant.

 After further training, in March 1944, John was appointed Lieutenant and platoon leader of 30 men in 6 Platoon, 2 Company, 1 Motor Battalion, Guards Brigade, who in armoured personnel carriers had to support the forward units of the armoured battalion.

On 24 June 1944, his division landed via the artificial harbour at Arromanches. John received his baptism of fire on 18 July during Operation Goodwood and subsequently took part in all the Guards Division's battles in Normandy.

On 29 August he crossed the Seine at Vernon and on 3 September the division reached Brussels in a veritable triumph.

The advance continued to the Dutch border, and when Operation Market Garden started on 17 September 1944, the Guards Division and John's platoon were again at the centre of events. 

During the fighting around the railway bridge in Nijmegen, a force – including John's platoon – was surrounded for almost two days before it was possible to link up with the rest of the division again.

After a week's leave in January 1945, John continued service with his platoon during the attack into Germany.

On April 9, they had reached about 50 kilometres into Germany, but at the villages of Dalum, 40 km north-west of Osnabrück, they ran into fierce resistance, during which John fell.

John Christmas Møller is today buried in the British military cemetery on the southern edge of Sage, 25 km south of Oldenburg.