Johanna belonged to the Matheson merchant family, which in contemporary Trondheim is mostly known for the Matheson building on Olav Tryggvasons street (the location of the Mox-Næss bookshop earlier, later Norli bookshop). The family lived for large parts of the year at their Solheim property in Rotvoll, then on the outskirts of Trondheim. The remainder of this estate disappeared when Statoil built it's new office building there in 1991.
In 1927 Johanna Matheson was employed at the Trondheim public library. The profession of librarian suited her well as it allowed her to exploit her social skills and cultural interests in her day-to-day encounters with the public. For some years she combined her library post with work in the office of Nidaros diocese.
In 1993, at the age of 32, she graduated from upper secondary school (gymnas) and then left for London to pursue tertiary librarian training. In 1934 she returned to Trondheim, getting a job at the Main Public Library on Kongens gate (street). This was to be her place of work for the rest of her life.
Camouflaging this was easy, covered by the day-to-day bustle in the library. But the operation was discovered and in November 1942 Johanna and her sister Thora were arrested. They were kept prisoners in Vollan prison for female inmates in Trondheim, and at Falstad and Grini.
In the summer of 1944 Johanna was sent to the infamous Ravensbrück camp in Germany. After this long period of imprisonment her health deteriorated. She died from an angina attack on 15 November 1944. 50 years after her death Johanna Matheson's memorial plaque was unveiled in Trondheim Public Library.