Dorian Leigh Parker was born in San Antonio, Texas, to George and Elizabeth Parker. Her parents married when they were around 18 and 17 years-old and Elizabeth promptly gave birth to three daughters in quick succession: Dorian (1917), Georgiabell (1918), Florian (1919). Fifteen years after the birth of her first daughter, she gave birth to her fourth daughter, Cecilia (1932) (who became known as model/actress Suzy Parker) . The family later moved to Queens; George Parker invented a new form of acid etching which brought wealth to the family .

Dorian claims she graduated from high school at the age of 15 because she was an intellectual and took many classes at once. As a 16-year-old freshman at Randolph-Macon College in Lynchburg, Virginia, Leigh met her first husband, Marshall Powell Hawkins, who was 25-years-old. As a sophomore, she secretly married Hawkins in North Carolina and had two children: Thomas Lofton Hawkins and Marsha Hawkins. The couple separated when Dorian was around 20.

Dorian then worked as a file clerk at a department store in Manhattan and as a tabulator keeping track of radio program ratings. Dorian found that she had an aptitude for math, mechanical engineering, and drawing. She began to go to night school at Rutgers and then got a mechanical engineering degree from New York University, a degree that was quite rare for a single, young mother in the early 1940s.

Dorian worked at Bell Laboratories and then, during World War II, she was a tool designer at Eastern Air Lines (with their Eastern Aircraft division). Dorian assisted in the design of airplane wings, beginning at 65 cents an hour and ending up with an hourly wage of $1.00. After failing to be promoted because she was a woman, Dorian quit and took a job with Republic Pictures as an apprentice copywriter. While writing advertising copy in 1944, she met a woman at work, Mrs. Wayburn, who encouraged Dorian to try modeling.

Taking Mrs. Wayburn's advice, Dorian had professional photos taken and went to the Harry Conover modeling agency. At 27, Dorian was not only old by modeling standards, but at barely 5'5", she was much shorter than the other models at the agency. Upon meeting Conover, he sent her to meet Diana Vreeland, the editor of Harper's Bazaar. Dorian met with Vreeland and fashion photographer Louise Dahl-Wolfe who were intrigued by her zig-zagged eyebrows. Vreeland warned her, "Do not-do not do anything to those eyebrows!" Vreeland asked Dorian to return the next day, to be photographed for the cover of a 1944 issue of Harper's Bazaar, her very first modeling assignment. They thought Dorian was around 19 or 20-years-old. Later they were shocked to discover her real age and that she already had two children.

Dorian's parents thought modeling was not respectable, so Dorian Leigh Parker used only her first and middle name during her career. When Dorian became an enormous success though, they thought it was acceptable that their youngest daughter, Suzy, use the Parker last name, when she also became a famous model.

Dorian instantly became busy with modeling assignments, landing on the covers of major magazines such as "Vogue," "Harper's Bazaar," "Paris Match," "LIFE," and "Elle," Because of her schedule, Dorian's two children were sent to live with her parents in Florida, while she was based in New York and traveling to Europe.

One of her neighbors, in her brownstone apartment building in the late 1940s, was visited often by his friend Truman Capote. Capote noticed that Dorian dated countless men, including a few, very famous, black singers and musicians of the era. Capote saw that Dorian took her personal and modeling phone calls at a candy store across the street, and kept cats for company. Capote called her "Happy-go-lucky." It is believed that Dorian was the inspiration for Capote's character, Holly Golightly, in his famous 1958 novel and 1961 motion picture Breakfast at Tiffany's.

In 1946, Dorian appeared on the cover of six American Vogue magazines. She worked with famous fashion photographers Irving Penn, John Rawlings, Cecil Beaton, and Paul Radkai. On one assignment, she argued with Paul's wife Karen Radkai, who wanted to take many extra and free photos of Dorian for her portfolio. Karen wanted to be a "Vogue" fashion photographer like her husband. When Dorian balked at having to pose for Karen, she warned Dorian she would "ruin her." Indeed, Vogue never used Dorian again, and Karen became a Vogue photographer.

Dorian easily transitioned to working with Harper's Bazaar's new, young photographer, Richard Avedon. Avedon would become one of the most famous photographers in history.