Joseph immigrated to the United States in 1933 after finishing university in Leipzig. His parents and brother had left Germany earlier for the United States. Joseph attended Columbia University. From 1940 to 1943 he was assistant editor for a New York German-Jewish newspaper. In 1944, he worked in the American embassy in Britain as a propaganda analyst. He went to Nuremberg, Germany, as an interpreter in 1946. He analyzed materials and transcripts, and participated in many interrogations for the Nuremberg trials.
The only one who, as I've said before, admitted, on occasion, responsibility for what was done over an order that showed his signature was Göring. But he too was an inferior...and a tip-off of an inferior being...and a tip-off that, uh, that, uh signaled, that betokened that inferior being, was his demeanor and attitude toward, I don't know whether I mentioned that before, toward, uh, the Big Four. To the French, the weakest of the Allies, he was, uh, patronizing, if not scornful. To the Americans, uh, he tried to impress us as, uh, as a kind of guy who would be a good fellow to the buccaneering, uh, Americans who were suckled on, uh, Hollywood films. To the British, who were precise, cold, correct, he tried to emulate a gentlemanliness because he respected the British. But when he saw a Russian, he winced. The minute a Russian officer entered the interrogation room he winced and cringed slightly. He knew of no posture that would impress a Russian. He was scared to death of any Russian and every Russian that entered the room, the interrogation room.