He grew up with his two younger brothers, Holger Marius Nielsen (1905–1993) and Povl Erik Nielsen (1909–1995) in Glostrup, 10 kilometres west of Copenhagen.
Nielsen's upbringing took place with his two younger brothers, Holger Marius Nielsen (1905–1993) and Povl Erik Nielsen (1909–1995), in the suburb of Glostrup, situated about 10 kilometers west of the Danish capital city, Copenhagen.