Singer's parents were Austrian Jews who immigrated to Australia from Vienna after Austria's annexation by Nazi Germany in 1938. They settled in Melbourne, where Singer was born. His grandparents were less fortunate: his paternal grandparents were taken by the Nazis to Łódź, and never heard from again; his maternal grandfather David Ernst Oppenheim (1881–1943), a teacher, died in the Theresienstadt concentration camp. Oppenheim was a member of the Vienna Psychoanalytic Society and wrote a joint article with Sigmund Freud, before joining the Adlerian Society for Individual Psychology. Singer later wrote a biography of Oppenheim.