In 2003, she founded By Malene Birger in partnership with Danish clothing group IC Group. She remained at the helm until 2014 when she sold her share of the company to IC Group.
Since 2017, By Malene Birger has been designed by Mathilde Torp Mader. Always one of the highlights of Coopenhagen fashion week, the brand has become synonymous with the Scandinavian modern aesthetic; creating intelligent, chic clothes for the modern woman.