Kjeld was born 27 December 1947 in Billund, Denmark. His father, Godtfred Kirk Christiansen worked with his grandfather, Ole Kirk Christiansen, in the family business: LEGO. As a child, he often inspired and tested new model concepts and their building instructions for their company. He also appeared on many of the company's packages and marketing materials. In 1979, he became president and CEO of the LEGO Group. Kjeld introduced themes, Minifigures, LEGO.com, Mindstorms and licensed properties such as Star Wars. In 2004, he stepped down as president and CEO to focus on his role as owner of the LEGO Group and Vice-Chairman