Johannes (Jo) Hammerborg was born on 4 February 1920 in the city of Randers in the Midtjylland region of Denmark, the fourth of seven children. After graduating from school in Randers he trained as a silversmith in Silkeborg and Randers between 1942 and 1944 before joining Copenhagen's prestigious Kunstakademiet, the Royal Danish Academy of Fine Arts. Exhibitions of Hammerborg's paintings were held in Randers in 1944, 1945, 1946 and 1947. In addition to his studies during the war years, Hammerborg became involved with resistance groups against the German occupation of Denmark that sabotaged railways and in particular the airfield at the Nordylland city of Aalborg. In 1949 he began work as a silversmith at Georg Jensen, where he remained for nine years until 1957, leaving to take up a position as head of design at Fog & Mørup. In 1957 Jo Hammerborg began work as head of design at Fog & Mørup. In this role he was not only a prolific designer, creating over 60 lamps and bringing a new modernist aesthetic to the company, but also collaborated with other designers to adapt their designs to meet F&M production requirements. He worked closely with Holmegaard glassworks during the development of both his own glass lamps and those by Holmegaard's Jacob E Bang, and with Royal Copenhagen during F&M's collaborations with the porcelain factory. A similar level of engagement took place with Sidse Werner & Leif Alring on their Formland project. Jo Hammerborg's lighting designs won many prizes, amongst them a CICi first prize in 1965 for the Nova and four iF Product Design Awards in 1969 for the Classic, Tunika, Saturn and Diskos. In 1980 Hammerborg left F&M to set up his own lighting design business. His departure coincided with the demise of the company as it underwent a series of mergers, first with Lyfa and later with Horn, at which point the F&M brand ceased to exist altogether.