Regarded as one of the greatest and most inscrutable movie stars ever produced by Metro-Goldwyn-Mayer and the Hollywood studio system, Garbo appeared in both the silent and the talkies era of film-making. She was one of the few silent movie actresses to successfully negotiate the transition to sound, which she achieved in 1930's Anna Christie, for which she was nominated for an Academy Award. She appeared twice as the fabled Anna Karenina, once in 1927's silent film, Love, and in 1935's Anna Karenina, for which she received the New York Film Critics Circle Award for Best Actress. She considered her 1936 performance as the courtesan Marguerite Gautier as her best performance and that role in Camille earned her a second Academy Award nomination. During the World War II era, MGM attempted to recast the somber and melancholy Garbo into a comic actress, in 1939's Ninotchka, which MGM touted with the tagline, "Garbo laughs," followed by 1941's Two-Faced Woman, in which Garbo danced and sang. For Ninotchka, Garbo was again nominated for an Academy Award; Two-Faced Woman did well at the box office, but was a critical failure. Garbo received a 1954 Honorary Academy Award.

Garbo reportedly entered into a variety of intimate liaisons with men and women, but her long-standing relationship appeared to be with the leading man, John Gilbert, whom she agreed to marry but she failed to show up for her wedding. In her retirement, during which she became increasingly reclusive, she lived in New York City. A 1986 Sidney Lumet film, Garbo Talks, reflected the continuing popular obsession with the star. Until the end of her life, Garbo-watching became a sport among the paparazzi and the media, but she remained elusive. She died in 1990.

Garbo, born Greta Lovisa Gustafsson in Stockholm, Sweden, was the youngest of three children of Karl Alfred Gustafsson (1871–1920), an unskilled worker, and his wife, Anna Lovisa (née Karlsson) (1872–1944). Greta's older brother and sister were Sven Alfred (1898–1967) and Alva Maria (1903–1926).

Karl and Anna Gustafsson had migrated from the farming country of southern Sweden drawn by the hope of work and housing in the capital. The family lived in a small, cold-water tenement apartment at Blekingegatan No. 32 in Södermalm, a working-class district of Stockholm 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 are filled with anxiety, as if there is 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.

The young Greta, daydreaming and shy, hated school, did not play much, but was drawn to the world of theater from an early age and dreamt about becoming an actress.

In June 1919, age 13, Greta graduated from school, and typically for a Swedish working-class girl at that time did not pursue further education; she would later express an inferiority complex about this fact. Despite or because living in near poverty, young Greta maintained her moonstruck attitude toward the stage: she played amateur theatre with her friends, she had a schoolgirl crush on Carl Brisson, the heartthrob matinee idol of his day, laying siege to his dressing room at the Mosebacke Theater, and she announced that she would one day be as great as Naima Wifstrand, another one of her favorites and the reigning star of the Swedish theatre and light-opera.

Alva, Greta's sister, worked in an insurance office as a stenographer, and Sven, Greta's brother, had married and moved in with his wife and child - they were now living seven in the three room apartment. The mood at home became further strained when Greta's father began missing work - he had worked odd jobs as street cleaner, grocer, factory worker and a butcher's assistant - and when in winter 1919 the Spanish flu had spread throughout Stockholm and Karl Alfred fell ill and lost his job, Greta's mother found work at a jam factory, while Greta stayed at home looking after her father and once a week took him to the hospital for treatment.

When Greta was 14 years old, her father, to whom she was extremely close, died. Her first job was as a soap-lather girl in a barbershop. One day a young man by the name of Kristian Bergström, son of the founder of PUB department store, Paul U. Bergström, entered the barbershop for a shave. He eventually offered her a job as a clerk at PUB. She accepted the offer and started to work for PUB in July 1920, where she also modeled for newspaper advertisements. She appeared in two short film advertisements, the first for PUB, and they were eventually seen by comedy director Erik Arthur Petschler. He gave her a part in his upcoming film Peter the Tramp (1922).

From 1922 to 1924, Greta Gustafsson studied at The Royal Dramatic Theatre's Acting School in Stockholm. There, she met director Mauritz Stiller who worked as a teacher. He trained her in cinema acting technique, gave her the stage name Greta Garbo, and cast her in a major role in the silent film The Saga of Gosta Berling in 1924, a dramatization of the famous novel by Nobel Prize winner Selma Lagerlöf, where she played opposite Swedish film actor Lars Hanson. She followed this appearance with a part in the 1925 German film Die freudlose Gasse (The Joyless Street or The Street of Sorrow) directed by G. W. Pabst and co-starring Asta Nielsen.