Born in Frederiksberg, Gadegaard studied painting at the Royal Danish Academy of Fine Arts from 1940 to 1946 under Sigurd Wandel, Kræsten Iversen, Aksel Jørgensen and Vilhelm Lundstrøm.
Forced to leave Denmark during the Second World War, he also studied at the Royal Swedish Academy of Arts under Otte Sköld (1944–1945).
[1] Gadegaard's early paintings were Naturalistic but from the end of the 1940s became Abstract, influenced by the Constructivist trend he encountered in Paris.
While the factory no longer exists, many of Gadegaarde's paintings with their large angular shapes and bright colours can still be seen in the Herning Art Museum.
[4] Gadegaarde's work is Herning is considered to represent an important development in the recent history of Danish art.