Suellyn Lyon was born in Davenport, Iowa, the youngest of five siblings born to Sue Lyon (née Karr) and James Lyon. Sue Karr Lyon was 42 years old when she was widowed, when Suellyn was just 10 months old. Her mother worked in a hospital to provide for her children, and money was tight. The family then moved to Los Angeles in hopes that Suellyn could help out financially as a model.

She duly got jobs modeling for JC Penney, and doing a commercial, which featured her bleached blonde hair. She landed small parts on Dennis the Menace (1959) and Letter to Loretta (1953). Director Stanley Kubrick saw Sue on the show and suggested to his partner that they should see her for the role of Lolita (1962). She was signed by the Glenn Shaw agency, and Pat Holmes, an agent, brought her down to Kubrick for audition, and won the part of Lolita.

In 1964, Sue married Hampton Fancher III but the marriage, like the four that would follow, would end in divorce. She was appearing at the time in such movies as 7 Women (1965), The Flim-Flam Man (1967) and Tony Rome (1967). Her second husband was Roland Harrison, an African-American photographer and football coach. The controversy over their marriage made them decide to move to Europe. She continued in movies like Evel Knievel (1971), Tarot (1973), and Una gota de sangre para morir amando (1973), but wound up divorcing Harrison, in part due to the fallout over the controversy and other problems.

Sue met Gary "Cotton" Adamson at the Colorado State Penitentiary, where he was serving time for murder and robbery. She worked as a cocktail waitress and lived in a hotel in Denver nearby. She married him in 1973 and began working for prison reform and conjugal rights. Unfortunately this was another short-lived marriage as she divorced him after he committed yet another robbery. More films followed including Smash-Up on Interstate 5 (1976), The Astral Factor (1978), Towing (1978), Crash! (1976), Don't Push, I'll Charge When I'm Ready (1971) and her final film, Alligator (1980).

Sue married Edward Weathers in 1983, but the marriage ended a year later. She married a radio engineer, Richard Rudman, but that marriage, like the four before it, ended in divorce.

Sue Lyon died in 2019, aged 73. She was survived by her only child, a daughter, Nona Harrison (from her marriage to Roland Harrison).