She was born Estelle Eggleston in Yazoo City, Mississippi, the only child of Thomas Ellett Eggleston and his wife Dovey Estelle (née Caro). One of her great-grandfathers was Henry Clay Tyler, an early settler from Boston and a jeweler who gave the Yazoo City courthouse cupola its clock.
When Stevens was 4, her parents moved to Memphis, Tennessee, where they lived on Carrington Road near Highland Street. Her father was an insurance salesman, and her mother was a nurse. Stevens attended St. Anne's Catholic School on Highland Street and Sacred Heart School on Jefferson Avenue, finishing her final year of high school in 1955 at the Memphis Evening School at Memphis Tech High School. Throughout the late 1950s and 1960s Stevens achieved success as a model. When high-speed Ektachrome film was introduced in 1959, Stevens was the first person ever photographed for a formal portrait by the light of a single candle and several reflectors for the cover of a photography magazine. In January 1960, she was Playboy magazine's Playmate of the Month, and was also featured in Playboy pictorials in 1965 and 1968. She was included in Playboy magazine's 100 Sexiest Stars of the 20th Century, appearing at number 27. During the 1960s she was one of the most photographed women in the world.
- She studied at St. Anne's Catholic School on Highland Street and Sacred Heart School on Jefferson Avenue. In 1955, she graduated from the Memphis Evening School at Memphis Tech High School.
- She was 16 years old when she married electrician Noble Herman Stephens on December 1, 1954. On June 10, 1955, she gave birth to their son, actor and filmmaker Herman Andrew Stevens. While the couple parted ways 1957, both Stella and her son kept using a variation of his surname in their stage names.
- Stevens attended Memphis State College. It was during this period that she developed an interest in acting and modelling. Her acting in the college play ‘Bus Stop’ garnered her some attention. Her performance even received positive reviews from ‘The Memphis Press-Scimitar.’