Johansen was born in Copenhagen on 7 July 1921 and was serving with the 8th Battalion The Buffs (Royal East Kent Regiment) before being recruited by SOE on 12 May 1943 and during training showed the required aptitude to teach members of the resistance sabotage. By the time Johansen arrived in Denmark by parachute there were 57 other agents building up resistance to support an eventual allied invasion and until the deployment of SOE there was virtually no effective resistance in Denmark.
Throughout 1943 it was mainly sabotage stores which was dropped into Denmark and as the number of resisters increased thousands of weapons were also dropped.
In 1943 there were only a few hundred resisters, in 1944 there were around 10,000 and eventually rose to 50,000 men and women (estimated as one per cent of the population). During the runup to D-day the resistance organisations were engaged in widespread sabotage which helped tie down German forces that would have been sent to northern France and SOE was also instrumental in bringing together various political groups.
Hans Johansen was captured at a safehouse by the Gestapo in Copenhagen on 25 July 1944 and because torture for information was inevitable, he swallowed his ‘L’ Pill (Cyanide) and died at the safehouse in under thirty seconds.