Santesson's monumental sculptures and intimate portraits of her contemporaneous women artists are regarded as her greatest creative triumphs.

While in Stockholm, Santesson was a student of the Royal Swedish Academy of Fine Arts, but later left to complete her education in Paris.

While in Algeria, she painted a portrait entitled Mr Iffa, which was later exhibited beside the work of the Finnish artist Engelbert Bertel-Nordström at the Konstnärshuset in Stockholm.

During this time, she painted portraits of her friends who were well-known contemporaneous artists, including Naima Wifstrand, Marianne Frestadius [sv], and Hanna Rydh.

Her studio became a meeting place of for her old friends, where Berta Hansson worked on the sketches, Siri Derkert was in charge of the sculptors, and Maj Bring served as a model.

In a review, Swedish art critic Ulf Linde said, "Ninnan Santesson's sculptures and drawings have an incredible vibrato on all of the form's surfaces.