Poul Kjaerholm took classes at Hjørring Teknisk Skole, while apprenticed to master cabinetmaker Thorvald Grønbech from 1944-49. Thereafter he attended the Copenhagen School of Arts and Crafts under Hans J. Wegner until 1952, where he later worked as an assistant until 1956.
During 1952/53 Kjaerholm worked at the Fritz Hansen furniture factory in Copenhagen and while also creating innovative furniture prototypes using molded materials. From 1953 to 1980 Kjaerholm designed several exhibtions besides teaching at the department of Furniture Design and Spatial Art at the School of Architecture, Royal Danish Academy of Fine Arts. In 1976 he succeeded Ole Wanscher as professor at the same institution.
In 1955 Kjaerholm began a life-long partnership with Ejvind Kold Christiansen and two years later he designed the lounge chair PK 22. The chair was one of the first of Kjaerholms designs that was made of steel, assembled in a way to display the material’s inherent strength. At the Milan Triennal the same year Kjaerholm was awarded a Gran Prix for the PK 22. The following year, Kjaerholm was awarded the Lunning Prize together with Swedish designer glass designer Ingeborg Lundin, which gave them both a possibility to exhibit their designs in New York.
For the Milan Triennale in 1960, Kjaerholm was responsible for the Danish section, which was distinguished with a Grand Prix and a Gold Medal. During the same year Kjaerholm also received the Eckersberg Medal from the Royal Danish Academy of Fine Arts.
In 1961 Kjaerholm designed an exhibition with his own name at the Metz & Co. store in Amsterdam, as well as designing the folding stool PK 91, a great example of his use of historic design for steel furniture, in this case Kaare Klints Propeller Stool from 1930. Both PK 22 and PK 91 are a part of the collection at the Museum of Furniture Studies.
In 1964 Kjaerholm was the recipient of the Knud V. Engelhardt Memorial Grant and the following year he and photographer Keld Helmer-Petersen had the joint exhibition Structurer (eng. Structures) på Ole Palsby Galleri in Copenhagen. In 1967 Kjaerholm designed the Danish participation at the World Fair in Montreal.
During the 1970’s Kjaerholm received the Danish Furniture Manufacturers’ Prize twice, in 1971 for PK 27 and in 1977 for the Louisiana chair. In 1972 he was also awarded the Danish ID Prize. Poul Kjaerholm passed away in 1980 at the age of 51. He is represented at several major museums such as the Museum of Modern Art in New York, the Danish Modern Museum in Copenhagen and the Victoria & Albert Museum in London.