Kai Kristiansen was born in Denmark in 1929. During his career as a furniture designer, he crafted pieces that came to represent the Danish style of the late 20th century. Kristiansen apprenticed as a furniture maker and concluded his apprenticeship in 1948. He enrolled at the Academy of Fine Arts in Copenhagen in 1950 and studied furniture design under Kaare Klint.

In the mid 1950s, Kristiansen launched his own design office. At this time, he began developing what would become some of his most famous works, including the #42 dining chair and sofa/chair series #121. Kristiansen also organized several furniture events during his lifetime. He was responsible for a regional furniture fair from 1956 to 1965 and was one of the key contributors to the Scandinavian Furniture Fair from 1966 to 1970.

Throughout his career, Kristiansen designed writing desks, tables, sideboards, chairs, bar cabinets and TV stands. His works primarily were manufactured from teak or rosewood and designed to provide consumers with the perfect mix of flexibility and style. Kristiansen ultimately was a part of the mid century modernist movement. His works personified clean-lined furniture. In addition, Kristiansen worked with numerous furniture manufacturers during his career, which helped him share his designs with the world.