Rosing was born in 1925 in
Ilulissat (Jakobshavn), Greenland, son of priest and artist Otto Rosing. In 1947–1948, he was a student at the Akademiet for Fri og Merkantil Kunst in Denmark. In 1952, he married Dagny Rosing (maiden name Nielsen), who is Danish. That year, Rosing introduced domesticated
reindeer to
Nuup Kangerlua, and he managed a reindeer station in Itinnera along one of the
fjords near
Nuuk until 1959. He and his family lived for many years in a suburb of
Copenhagen,
Denmark. Jens and Dagny Rosing had 3 boys and one girl. == Career ==