Spacek was born on December 25, 1949, in Quitman, Texas, the daughter of Virginia Frances (nee Spilman; December 18, 1917 - November 10, 1981) and Edwin Arnold Spacek Sr. (July 3, 1910 - January 7, 2001), a county agricultural agent. Her mother, who was of Polish, English and Irish descent, was from the Rio Grande Valley of Texas. At age 6, she performed on stage for the first time, appearing in a local talent show.

Spacek worked for a time as a photographic model (represented by Ford Models) and as an extra at Andy Warhol's Factory. She appeared in a non-credited role in his film Trash (1970). With the help of her cousin, actor Rip Torn, she enrolled in Lee Strasberg's Actors Studio and then the Lee Strasberg Institute in New York. Her first credited role was in Prime Cut (1972), in which she played Poppy, a girl sold into sexual slavery. The role led to television work, which included a guest role in The Waltons, which she played twice in 1973. Spacek received international attention after starring in Terrence Malick's Badlands (1973), in which she played Holly, the film's narrator and a 15-year-old girlfriend of mass-murderer Kit (Martin Sheen). Spacek has described Badlands as the "most incredible" experience of her career. On the set of Badlands, Spacek met art director Jack Fisk, whom she married in 1974. Spacek's iconic and career-defining role came in Brian De Palma's film Carrie (1976), in which she played Carietta "Carrie" White, a shy, troubled high school senior with telekinetic powers. Spacek had to work hard to persuade director de Palma to engage her for the role. After rubbing Vaseline into her hair and donning an old sailor dress her mother made for her as a child, Spacek turned up at the audition with the odds against her, but won the part. She was nominated for the Academy Award for Best Actress for her work in the film. Spacek had previously been the set dresser for DePalma's film Phantom of the Paradise (1974). After Carrie, Spacek played the small role of housekeeper Linda Murray in Alan Rudolph's ensemble piece Welcome to LA (1976) and cemented her reputation in independent cinema with her performance as Pinky Rose in Robert Altman's classic 3 Women (1977). Altman was deeply impressed by her performance, having stated: "She's remarkable, one of the top actresses I've ever worked with. Her resources are like a deep well." Brian de Palma added: "[Spacek is] a phantom. She has this mysterious way of slipping into a part, letting it take over her. She's got a wider range than any young actress I know." Spacek also helped finance then-brother-in-law David Lynch's directorial debut, Eraserhead (1977) and is thanked in the credits of the film.

Whose film was that?
Andy Warhol's