Portman was born in Jerusalem, Israel. She is the only child of Shelley (née Stevens), an American homemaker who works as Portman’s agent, and Avner Hershlag, an Israeli citizen who is a fertility specialist and gynecologist. Portman’s maternal ancestors were Jewishimmigrants to the United States, from Austria and Russia (her mother’s family had changed their surname from “Edelstein” to “Stevens”). Her paternal grandparents were Jews who moved to Israel from Poland and Romania. Her paternal grandfather, whose parents died at Auschwitz, was an economics professor in Israel, and her Romanian-born great-grandmother was a spy forBritish Intelligence during World War II.
Portman’s parents met at a Jewish student center at Ohio State University, where her mother was selling tickets. They corresponded after her father returned to Israel, and were married when her mother visited a few years later. In 1984, when Portman was three years old, the family moved to the United States, where her father received his medical training. Portman, a dual citizen of the United States and Israel, has said that although she “really love[s] the States… my heart’s in Jerusalem. That’s where I feel at home.”