Princess Margaretha was born on 25 June 1899 at her parents' summer residence, the Villa Parkudden, at Djurgården in Stockholm.

In 1916 Margaretha's confirmation attracted enthusiastic press coverage; the event was said to mark the beginning of a new age for the Swedish royal house, which had lacked princesses for so long.

She lived a private life devoted to her family on the estate Bernstorffshøj in Gentofte and generally avoided publicity, and kept in close contact with her relations abroad.

She was interested in social issues in Sweden, and became the patron of several charity organisations in Denmark, and was the chairperson of Gentofte Børnevenner.

As a widow, she was often back in Sweden, where she would join other members of the Swedish royal house in representative duties at official ceremonies — most notably, the Nobel Prize.