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. 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, Lego Mindstorms and licensed properties. In 2004, he stepped down as President and CEO to focus on his role as owner of the Lego Group and vice-chairman of the board, while maintaining his role as chairman of the board of KIRKBI A/S, Lego Holding A/S and the Lego Foundation. Lego is privately held and is controlled by the Kristiansen family and their foundations.