Dan Jacobson was born 7 March 1929, in Johannesburg, South Africa, where his parents' families had come to avoid the persecution of Jews and to escape poverty in their European homelands. His father, Hymann Michael Jacobson, was born in Ilūkste, Latvia, in 1885. His mother, Liebe (Melamed) Jacobson, was born in Kelme, Lithuania, in 1896. Jacobson had two older brothers, Israel Joshua and Hirsh, and a younger sister, Aviva. His mother's family emigrated to South Africa in 1919, after the death of his grandfather. His grandfather, Heshel Melamed, was a rabbi, and refused to leave Lithuania after traveling to the United States and finding that many Jews were not following their religion. Jacobson later wrote in his memoir "Heshel's Kingdom" about his travels back to Lithuania to find out more information about his grandfather.