Oleg Cassini was born Oleg Cassini Loiewski, of Russian parents in 1913. His grandfather was Count Arthur Cassini who was Russian Czar Nicholas's ambassador to Washington during the McKinley and Theodore Roosevelt administrations. His mother was Countess Marguerite Cassini. His father was Count Alexander Loiewski. Oleg used his mother's name for his professional career.
He was educated in Florence at the English Catholic School and graduated from the Accademia delle Belle Arti in 1932.
In 1933 he worked briefly for his mother's dress salon, and then opened his own salon in Rome the same year.
In 1936, he went to New York and designed for various 7th Avenue stores until 1940 when he joined 20th century Fox in Hollywood.
Cassini married actress Gene Tierney on July 11, 1941 and designed her costumes for 7 of her films. As Tierney’s parents didn’t approve of the union, the couple eloped to Las Vegas, and used earrings as wedding rings. The couple had two daughters, Antoinette Daria Cassini (born October 15, 1943) and Christine “Tina” Cassini (born November 19, 1948). Tierney contracted German measles during her first pregnancy, and their daughter, Daria, was born deaf, blind and mentally retarded. Tierney had an affair with John F. Kennedy, and the couple were divorced on February 28, 1952, but he continued to design for occasional Hollywood films up till 1967.
By 1950, he was back on 7th Avenue in New York and during the 50's, his name was associated with glamorous ready-to-wear sheath dresses, knitted suits, jackets and cocktail dresses. He also designed extensively for Broadway and television.
Oleg was very much in love with Grace Kelly in 1953-54, and wanted to marry her. However she rejected him in favour of Prince Ranier of Monaco, whom she subsequently married.
In the 1960’s Cassini was chosen by Jacqueline Kennedy to design her state wardrobe. He worked closely with her in the evolution of her personal clothing style, creating many widely copied garments. He co-ordinated her wardrobe with hats, furs, gloves, shoes, and handbags. He made more than 100 dresses in the first year, and 300 during the course of the administration.
His house continues till today making elegant clothes for beautiful women. Cassini himself is in his 90's and lives a life of leasure in Connecticut. Oleg was awarded a Special Tribute award from the CFDA in 2003. Oleg Cassini has heard the rumours before, but he won't let them go undisputed. Arnold Scaasi's new book "Women I have dressed (and undressed)" states that Oleg copied French designs when dressing Mrs. Jacqueline Kennedy from 1960 to 1963 when she was America's First Lady. He said he has his own style, he didn't have to copy anyone.
He created the "Camelot" look that became synonymous with well-crafted style. He was known for such looks as the sheath and A-line dress, the turtleneck look for men, and the Nehru jacket.