Sassoon trained under Raymond Bessone, in his salon in Mayfair, of whom he said in 2010 that "He really taught me how to cut hair.... I'd never have achieved what I have without him." Sassoon opened his first salon in 1954 in London.
Sassoon stated his intentions in designing new, more efficient, hair styles: "If I was going to be in hairdressing, I wanted to change things. I wanted to eliminate the superfluous and get down to the basic angles of cut and shape."
Sassoon's works include the geometric perm and the "Nancy Kwan" hairstyles. They were all modern and low-maintenance. The hairstyles created by Sassoon relied on dark, straight, and shiny hair cut into geometric yet organic shapes. In 1963, Sassoon created a short, angular hairstyle cut on a horizontal plane that was the recreation of the classic "bob cut." His geometric haircuts seemed to be severely cut, but were entirely lacquer-free, relying on the natural shine of the hair for effect. Sassoon has been a key force in the commercial direction of hair styling.is Vidal Sassoon brand was applied to shampoos and conditioners sold worldwide, with a commercial campaign featuring the iconic slogan "If you don't look good, we don't look good." Former salon colleagues also bought Sassoon's salons and acquired the right to use his name, extending the brand in salons into the United Kingdom and the United States.
After moving to the United States, Sassoon sold his US$113 million-a-year company in 1983 to Richardson-Vicks. The company was bought over by Procter & Gamble in 1985, who he sued in 2003 for breach of contract and fraud in federal court for apparently neglecting the marketing of his brand name in favour of the company's other hair product lines such as Pantene The two parties settled the matter the following year.
In 2002, the chain of Vidal Sassoon salons had been sold to Regis Corporation. By 2004, it was reported that Sassoon was no longer associated with the brand that bears his name. Vidal Sassoon authored several books, including A Year of Beauty and Health co-written with his former wife, Beverly Sassoon. He also had a short-lived television series called Your New Day with Vidal Sassoon, which aired in the fall of 1980.
Sassoon was appointed Commander of the Order of the British Empire (CBE) in the 2009 Birthday Honours.
In 1982, Sassoon started the Vidal Sassoon International Center for the Study of Antisemitism, or SICSA, a research centre devoted to the non-political, interdisciplinary gathering of information about antisemitism.
After selling his company, he then worked towards philanthropic causes such as The Boys Clubs of America and the Performing Arts Council of the Music Center of Los Angeles via his Vidal Sassoon Foundation. He was also active in supporting relief efforts after Hurricane Katrina. It also funded educational pursuits on a need-basis in Israel and elsewhere. At the time of his death he had academies in England, the United States and Canada, while initiating plans to open new ones in Germany and China.