Irma Ida Ilse Grese was born to Berta Grese and Alfred Grese, a dairy worker, on 7 October 1923. Irma was the third of five children (three girls and two boys). In 1936, her mother committed suicide by drinking hydrochloric acid after discovering that Alfred had had an affair with a local pub owner’s daughter. Historian Peter Vronsky speculated that Alfred Grese joined the Nazi Party in 1937 and remarried in 1939.

Irma’s sister, Helene Grese, said at Irma’s trial that in primary school, when “girls were quarreling and fighting, [Irma] never had the courage to fight, but … ran away.” She left school in 1938, aged 15, and worked as an assistant nurse in the sanatorium of the SS.

She was soon promoted to a guard position at Auschwitz-Birkenau. In 1942, she became an Aufseherin (guard or overseer) at Ravensbrück, and in March 1943 she transferred to Auschwitz-Birkenau. In 1943 she fell out with her father, who was against her joining the SS entourage and expelled her from the house. In 1944, she was promoted to Rapportführerin, the second-highest rank possible for female KZ-wardens.

In early 1945, Grese accompanied a prisoner evacuation transport from Auschwitz to Ravensbrück. In March 1945, she went to Bergen-Belsen along with a large number of prisoners from Ravensbrück. Grese was captured by the British Army on 17 April 1945, together with other SS personnel who did not flee.