Johannes (Jo) Hammerborg grew up on the outskirts of Randers in a regular middle-class family. He trained as a silversmith, participated in Denmark's resistance and struggle for freedom in 1940-45 as a saboteur, studied at the Royal Danish Academy of Fine Arts and worked as a silversmith at Georg Jensen. In 1957, he was hired as chief designer at the lamp manufacturer Fog & Mørup, where he worked until 1980.
He was a pronounced idea person and entrepreneur, who throughout his entire life initiated and developed the things he was passionate about. He was a key driving force for Fog & Mørup, and it was under his leadership that the company experienced their most creative and commercially successful period. With a distinct design philosophy, great insight in elimination technique and a profound understanding of form, function and aesthetics, he created over 180 different designs of lamps, several of which have received international awards. In 1980, Fog & Mørup underwent a series of mergers, and in the late 90s ceased production of his designs.