[1] Her parents were choir director and herbalist Axel Evald Hammer, and her mother was Thora Christine Svendsen.

[1] Hammer-Jensen's research focused on science in the classical world, particularly the works of Aristotle, Democritus and Heron.

[6] Her doctoral thesis advanced the idea that Democritus influenced Plato, and gained a substantial amount of attention after its publication.

[10] However this idea was criticised by others who believed the awareness of medicine shown by these authors was what would be expected by an educated person at the time.

[11] On 11 October 1905 she married teacher Jens Christian Jensen; he wrote a widely used school textbook on natural science.