Josef Kramer trained as a guard, and received his first assignment in 1934, to Dachau. He was quickly promoted in subsequent camps – Sachsenhausen and Mauthausen. On the eve of World War II, he was adjutant to the camp commandant himself – Franz Ziereis. He gained further experience in the same position at Auschwitz, watching Rudolf Hoβ manage the camp.

Further training earned him a promotion to manager (Schutzhaftlagerführer) and then camp commandant. He held these positions at Natzweiler-Struthof, the only concentration camp in what is now France, and then for several months at Auschwitz II – Birkenau. At the former, he personally supervised the murder of dozens of people in the gas chambers, whose bodies were prepared for August Hirt, a scientist at the University of Strasbourg. At Birkenau, he oversaw, among other things, the murder of 400,000 Hungarian Jews. Witnesses claimed that he took an active part in the selection on the railroad ramp, deciding on the life and death of those who arrived at the camp, sometimes personally murdering the prisoners. As Olga Lengyel, a writer who survived Auschwitz, recalled, Kramer “smashed the skull of a female prisoner with a stick” during a selection on the revetment (hospital) of the women’s camp. 

For his merits, he was transferred to the Bergen-Belsen camp as commandant in December 1944. About 15,000 people were held there at the time, but more prisoners from the so-called “death marches” that were organized from camps in the east were transferred there. In this way, the number of people at Bergen-Belsen quadrupled. Conditions in the camp were dire – there was a shortage of food and no medicine. In addition, epidemics broke out, including typhus and dysentery, and prisoners died of thirst, even though the camp was only 400 meters from the river. From these causes, 200-300 people died daily. His reign was so brutal that he earned the nickname “the beast of Bergen-Belsen.” Kramer took part in the crew’s favorite “sport” at the camp, which was shooting starving prisoners who walked near the kitchen. In the final weeks, when Kramer knew that the Allies would enter Bergen-Belsen, he tried to change his approach to the prisoners in the hope that he would not be arrested.

The camp was liberated on April 15, 1945, and Kramer did not escape, but surrendered to the British. The trial against him and the camp staff began in September 1945. During the trial, Kramer admitted that he forced Jews to enter the gas chambers on Himmler’s orders. He also claimed that he could not ignore the orders, but he also did not consider it a crime to kill them.

On November 17, 1945, he was sentenced to death by hanging; the sentence was carried out on December 13.