Lustig was born in Prague. As a Jewish boy in Czechoslovakia during World War II, he was sent in 1942 to the Theresienstadt concentration camp, from where he was later transported to the Auschwitz concentration camp, followed by time in the Buchenwald concentration camp. In 1945, he escaped from a train carrying him to the Dachau concentration camp when the engine was destroyed by an American fighter-bomber. He returned to Prague in time to take part in the May 1945 uprising against the German occupation.