The son of a carpenter who died when he was 8, Grünewald apprenticed as a baker but found work difficult to come by when the First World War ended and the demobilised soldiers entered the labour market.

[1] Leaving the army as an Unterfeldwebel in April 1931, Grünewald again struggled to find employment and so joined the Sturmabteilung (SA), the Nazi paramilitary organization.

"In the case the situation required it", camp commandants were authorized to carry out the punishments that "may significantly harm physical well-being."

[3] He was spared a harsher sentence on the grounds of his military service and the court accepting his claim that he "didn't wish for the death of ten women."

"[4][5] In March 1944, after serving nearly a month in prison, Grünewald was pardoned,[6] but stripped of his rank and ordered to fight on the Eastern Front as a common soldier.