Her father Axel Kjølbye was a solicitor and active member of the resistance movement during the German occupation of Denmark in the Second World War, using his office opposite the Gestapo headquarters in Sønderborg to hide in plain sight.
As a student she worked on excavations in Aarhus and Hedeby, both dating to the Viking era, and also spent a year at the University of Edinburgh, where she studied the Early Bronze Age under Stuart Piggott.
[3] In 1964 Kjølbye-Biddle joined the excavations at Winchester Cathedral, where she gained a reputation in English field archaeology as the "dynamic pipe-smoking young Danish woman [...] imposing new standards of rigour".
[1] The complex site revealed the remains of the original minster and other early medieval churches and shrines demolished to build the extant Norman cathedral, as well as thousands of Christian burials.
Kjølbye-Biddle and Biddle proposed that the mass burial was that of the Great Heathen Army that invaded England in 865 and overwintered in Repton in 873, however radiocarbon dating of the remains showed that they had accumulated over many years.