Ottesen was born in Floro, and grew up in Skien, where she attended theater school. She graduated from the Norwegian National Academy of Theatre in 1999. Ottesen worked in several theater productions, such as at Oslo Nye Teater and Centralteatret. She had roles in Wild Angels, The Avaricious, Rocky Horror Show, and West of Eden. She wrote and produced the show "Happy Happy", which played at the Café Stage at Oslo Nye Teater. At the National Theatre, she played Madame Bonacieux in The Three Musketeers and Chamomile in When the Robbers Came to Cardamom Town. Her last stage appearance (in 2006) was in When We Dead, a remake of When We Dead Awaken by Henrik Ibsen.
She appears in the films Detector (2000), Elsk meg i morgen (2005), and Tatt av kvinnen (2007). On television she has appeared in the series Gnomes in the Barn (2001), Lekestue (2002), and Nissene over skog og hei (2011).
