LOS ANGELES — With one high-profile haircut on the Paramount Studios lot, Vidal Sassoon vaulted to fame in Hollywood.

Flown in from London, he trimmed the tresses of Mia Farrow for her role in the film “Rosemary’s Baby” — a $30 haircut that he calculated cost $5,000, including airfare.

The 1967 event was staged inside a makeshift “salon” in a boxing ring. The film’s director, Roman Polanski, looked on as Sassoon gave the actress a pixie cut that would be copied by women the world over.

As a celebrity hairstylist, Sassoon helped launch the age of the signature hair salon, complete with designer-label prices. He also revolutionized women’s hair styling with his signature sleek, geometric cuts. His most enduring contribution was perhaps a simple one — he popularized the hand-held blow dryer.

Sassoon, who had leukemia, died Wednesday at his home in Los Angeles, a family spokesman said. He was 84.

When Sassoon opened a hair salon in 1970 in Beverly Hills, the opening-night party also took on a theatrical flair when hundreds of celebrities, fashion and otherwise, “roamed up and down three levels in a merry melee,” the Los Angeles Times reported.

He moved his corporate headquarters to Los Angeles in 1974 and built a beauty business with global reach made up of hair-care products, signature salons and training academies.

When Sassoon used a blow dryer to create his innovative hairstyles, what had been a novelty item turned into a standard appliance in salons and homes. Hair rollers and helmet-style dryers became all but obsolete as a result.

“His designs have shaped the late 20th century,” Richard Martin and Harold Korda, then curators at the Costume Institute of the Metropolitan Museum of Art in New York City, wrote in the introduction to the 1993 book “Vidal Sassoon, Fifty Years Ahead.” He brought “modernism to the medium of hair,” they wrote.

Television viewers across the country saw the man behind the name when he purred the memorable and satirized line in a 1976 commercial: “If you don’t look good, we don’t look good,” he said.

The London native said he never wanted to be a “crimper,” slang for a hairdresser. Yet he became the most influential crimper of his generation.

At 14, he had dropped out of school and, at his mother’s urging, took his first job in a hair salon.

“I kept thinking I would be spending my life up to my elbows in shampoo,” Sassoon wrote in his 1968 autobiography, “Sorry I Kept You Waiting, Madam.”

When he was about 20, he served as a volunteer soldier in Israel’s 1948 War of Independence and found that it gave him “a sense of dignity and the confidence that helped structure my future,” he later said.

After a decade laboring as a stylist in London, Sassoon finally captured fashion’s main stage in 1963 when he crafted an architectural haircut for fashion designer Mary Quant, then one of London’s bright young talents who is credited with inventing the miniskirt.

She wanted a new look for her, and her models, to wear in a fashion show. In sharp contrast to the reigning pouf of the day, he cut a blunt-edged bob that angled down toward her chin.

Fashion editors took note of the models’ haircuts, and Sassoon’s name quickly became associated with top fashion models, notably British cover girl Jean Shrimpton, and with young British pop musicians starting with the Beatles, whose blunt-cut bangs — done at the Sassoon salon — launched a unisex hair trend.

He followed his “Mary Quant bob” with two other looks that confirmed his taste and style. The first was a “five point” cut that resembled a bowl with peaks at the nape of the neck and in front of the ears. The following year he introduced an “asymmetric bob,” cut longer on one side than the other.

To get the flat, shaped effect he wanted, he phased out the hair curlers and stationary dryers typical of the day. His portable blow dryer and a styling brush became his main tools, along with his scissors.

“To me hair dressing means shape. It’s very important that the foundations should be right,” he wrote in his autobiography.

In interviews he said his low-maintenance hairstyle gave women greater freedom and independence, buzz words for the social revolution breaking loose in Europe and the U.S.

“In the ’60s, everyone let their hair down and I was there to cut it in very straight, geometric lines,” he later recalled.