She grew up with her younger brother residing with their parents on the Skaugum Estate, near Oslo. Her parents wanted to give their children the most normal upbringing they possibly could, in spite of their children's status. She attended local schools among other Norweigen children. She also participated in numerous after-school activities, such as singing in the choir, playing the flute, folk dancing lessons, and horseback riding.
In 1992, Princess Märtha Louise began attending Bjørknes Privatskole in Oslo. She subsequently pursued a physiotherapy education program at Oslo University College. After finishing the program, shecompleted her practical training in Maastricht, the Netherlands. In 1997, she was awarded her formal qualification as a physiotherapist, and in 2000 she qualified as a Rosen practitioner.
Princess Märtha Louise became engaged to Ari Behn on 13 December 2001. The couple were married in Nidaros Cathedral in Trondheim on 24 May 2002.
The Princess and her husband have three daughters:
- Maud Angelica Behn (29 April 2003)
- Leah Isadora Behn (8 April 2005)
- Emma Tallulah Behn (29. September 2008)
Princess Märtha Louise and her family live in Bærum, near Oslo.
She undertakes numerous patronages and royal duties on behalf of her family. She is very active in areas concerning persons with disabilities. She is also active as patron of seven organisations, and as Chair of Princess Märtha Louise's Fund. She has long been engaged in cultural work, and especially in disseminating traditional Norwegian fairy tales to a wider audience. Among other activities, she has starred in a storytelling series on Norwegian television. The Princess is the author of several books and audiobooks, and has participated in the production of television programmes for children.
The Princess established a sole proprietorship on 1 January 2002 under which she conducts her independent professional activities in the cultural sphere and as a Rosen therapist. As of that date she has been subject to Norwegian tax laws.
In 2007 The Princess established Astarte Education with Elisabeth Nordeng.