Born in Alexandria, Egypt, the daughter of a cigarette factory manager, she met her husband, Raymond Aghion (1921 - 2009), when both were seven years old in elementary school. He was born into a wealthy family of cotton exporters, but displayed early stirrings of the social consciousness that would later land him in political exile. Gaby and Raymond, both Jewish, married at the age of 19. The couple moved to Paris in 1945. In Paris the Aghions gravitated toward artists, becoming close to writers Louis Aragon, Paul Éluard and Tristan Tzara. Gaby launched Chloé in 1952. Raymond opened an art gallery in 1956, specializing in modern art.
According to the website of Chloé, Aghion rejected the stiff formality of 1950s fashion and created soft, feminine, body conscious clothes from fine fabrics, and called them “luxury prêt-à-porter”. Unique for their time, they were beautifully made clothes available off the rack. She set up her workshop in a maid's room above her large flat. In 1953, Gaby Aghion joined forces with Jacques Lenoir – he ran the business side and she ran the creative side. The duo put on the first Chloé show in 1956 at a breakfast at the Café de Flore, the epicentre of young intellectual Parisians of the 1940s and 1950s.
Aghion, now retired from the public eye, said: "Everything was yet to be invented, and this thrilled me." Aghion hired Karl Lagerfeld early in his career, and other emerging fashion designers. Her son, Philippe, recalls Lagerfeld coming to the company in the mid-1960s: "When he arrived from [the house of] Jean Patou, Karl was a shy individual. He and my mother made a fantastic team. He came into the spirit of Chloé." 
- Gabrielle, “Gaby” Hanoka.
- Alexandrie Info n° 35, décembre 2010. "Decès: Raymond Aghion, à Paris le 24 juin 2009, à l'âge de 88 ans; Raymond avait épousé Gaby Aghion, née Gabrielle Hanoka."
- Chloé: A 60-Year Tradition of Pretty Prêt-à-Porter. By Lauren Cochrane. guardian.co.uk, 2 October 2012.
- Chloé biography.
- Socha, Miles (2 December 2013). "Chloé Founder to Receive Legion of Honor". WWD. Retrieved 3 December 2013.
- Then And Now. Gaby Aghion founder and Clare Waight Keller designer of Chloe SA. By Diderich, Joelle. WWD, September 28, 2012.
- Chloé. Biographies. Gaby Aghion.
- Chloé at 60: the story of a fashion legend. Guardian, 2 October 2012.
- Chloé website
- Chloe by Helene Schoumann (published by Assouline, 2003).
- Gaby Aghion and Karl Lagerfeld revisit the past at an exhibition on the history of the Chloé label in Paris. The New York Times, October 17, 2012