Greta Lovisa Gustafsson was born in Stockholm, Sweden. She was the third and youngest child of Anna Lovisa Karlsson, (1872–1944.) and Karl Alfred Gustafsson (1871–1920). Garbo had an older brother, Sven Alfred (1898–1967), and an older sister, Alva Maria (1903–1926).
Her parents met in Stockholm. Her father made occasional trips from his home in Frinnaryd. He moved to Stockholm to become independent, and worked in various odd jobs. He married Anna, who had recently relocated from Högsby. The Gustafssons were impoverished and lived in a three-bedroom cold-water flat. They raised their three children in a working-class district regarded as the city’s slum. Garbo would later recall:
“It was eternally gray—those long winter’s nights. My father would be sitting in a corner, scribbling figures on a newspaper. On the other side of the room my mother is repairing ragged old clothes, sighing. We children would be talking in very low voices, or just sitting silently. We were filled with anxiety, as if there were danger in the air. Such evenings are unforgettable for a sensitive girl. Where we lived, all the houses and apartments looked alike, their ugliness matched by everything surrounding us.”