Working with his grandfather as a child, Kjeld often inspired and tested new model concepts and their building instructions for the Lego brand. 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.Today the company manufactures enough tiny pieces annually to circle the world 24 times over.
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 and companies foundations. Lego is still privately held and is controlled by the Kristiansen family and their foundations.
Kjeld and his wife, Camilla, live in Denmark and have three children and two grandchildren.