meeting Linda Blair

Blair started acting with a regular role on the short-lived Hidden Faces (1968–69) daytime soap opera. Her first theatrical film appearance was in The Way We Live Now (1970), followed by a bit part in the comedy The Sporting Club (1971).

In 1972, Blair was selected from a field of 600 applicants for her most notable role as Regan, the possessed daughter of a famous actress, in William Friedkin's The Exorcist (1973). The role earned her a Golden Globe and People's Choice Award for Best Supporting Actress as well as an Academy Award nomination for Best Supporting Actress. Film critic and historian Mark Clark notes that in her performance, "Blair matches [adult co-star] Ellen Burstyn note-for-note. Despite the film's critical successes, Blair received media scrutiny for her role in the film, which was deemed by some as "blasphemous," and Blair has said the film had significant impact on her life and career. After the film's premiere in December 1973, some reporters speculated about Blair's mental state, suggesting the filming process had resulted in her having a mental breakdown, which Blair denied, and she would later receive anonymous death threats. To combat the rumors and media speculation surrounding her, Warner Bros. sent the then-14-year-old Blair on an international press tour in hopes of demonstrating that she was "just a normal teenager.

After the Exorcist press tour concluded, Blair starred opposite Kim Hunter in the wildly controversial television film Born Innocent (1974), in which she plays a runaway teenager who is sexually abused. The film was criticized by the National Organization for Women, the New York Rape Coalition, and numerous gay and lesbian rights organizations for its depiction of female-on-female sexual abuse; the Lesbian Feminist Liberation dismissed the film, stating: "Men rape, women don't," and regarded the film as "propaganda against lesbians. After filming Born Innocent, Blair also had a supporting part as a teenaged kidney transplant patient in the disaster film Airport 1975 (1974), which was critically panned by a success at the box office. A steady series of job offers led Blair to relocate to Los Angeles in 1975, where she lived with her older sister, Debbie. Between 1975 and 1978, she would have lead roles in numerous television films: Sarah T. – Portrait of a Teenage Alcoholic (1975), as a teenager who becomes addicted to alcohol; Sweet Hostage (1975) opposite Martin Sheen, in which she plays a kidnapping victim; and Victory at Entebbe (1976), a war drama starring Anthony Hopkins and Elizabeth Taylor.

In 1977, Blair reprised her role as Regan in the Exorcist sequel, Exorcist II: The Heretic (1977), garnering a Saturn Award nomination for Best Actress of 1978.[2] The film was a critical and commercial failure, however, and at the time was the most expensive film ever made by Warner Bros. studios.[16] After filming Exorcist II: The Heretic, Blair took a year off from acting and competed in national equestrian circuits under the pseudonym Martha McDonald.[5] In 1978, she made a return to acting in the Wes Craven-directed television horror film Stranger in Our House (re-titled Summer of Fear), based on the novel by Lois Duncan.[17] and also with the lead role in the Canadian production Wild Horse Hank, in which she utilized her equestrian skills to play a college student saving wild horses from ranchers