Rudolf Oppenheimer was born on 1 October 1931 in Berlin, the son of a liberal, assimilated Jewish family. His older brother, Paul, had been born in 1928, also in Berlin. In 1936, the family decided to leave Nazi Germany. After spending several months in London, where Rudolf's sister, Eve, was born, the family settled in the Netherlands in September 1936. In mid-1943, Rudolf Oppenheimer and his family were taken to the Westerbork transit camp in the Netherlands. Because their daughter Eve had been born in Great Britain, the family met the criteria for being exchanged in return for Germans interned abroad. As a result, they were transported to the Bergen-Belsen concentration camp in January 1944. Rudolf Oppenheimer's mother, Friederike, died there in January 1945, followed by his father, Hans, in March. Their three children, including Rudolf, were transported by train from the Bergen-Belsen concentration camp just a few days before the liberation. They were finally liberated by Red Army soldiers on 23 April 1945 in Tröbitz (Brandenburg).
In June 1945, Rudolf Oppenheimer returned to the Netherlands with his siblings, where he initially lived in an orphanage. In November 1945, he emigrated to Great Britain, where he earned a degree in electrical engineering. From 1956 he worked for the Shell Group in the Netherlands. He retired in 1990 and returned to Great Britain in 1996. Since then, he has talked to numerous groups of schoolchildren and British soldiers about his memories of Nazi persecution.