Born in Iceland, Matthildur graduated with a BMus degree in Performance from the Iceland Academy of the Arts in 2007. She continued her studies with Andrew West at the Royal Academy of Music in London, graduating with an MA degree in Piano Accompaniment. Matthildur graduated with MMus in Repetiteurship from the Alexander Gibson Opera School at the Royal Conservatoire of Scotland in June 2014. During her studies, she was on a full scholarship and was also awarded the James H. Geddes Répétiteur Prize. Matthildur has been involved in opera productions with The Icelandic Opera, British Youth Opera, The Royal Conservatoire of Scotland, Clonter Opera, Edinburgh Grand Opera, Lyric Opera Studio Weimar, Scottish Opera and Royal Academy Opera. Matthildur now works as an accompanist and a coach at The Iceland Academy of the Arts and at the Reykjavik College of Music.