Primarily self-taught, Alberto Morillas got his start in perfumery at the age of 20, inspired by an article in Vogue about French perfumer Jean-Paul Guerlain. He joined the Swiss fragrance and flavor company Firmenich in 1970 and has since created nearly 7,000 perfumes. He established himself with his 1975 creation Must de Cartier, the jewelery company's first perfume.

One of Morillas' standout creations is CK One, developed with Harry Fremont in 1994 for the Calvin Klein fashion house. In the 1990s, CK One had annual sales of about $90 million and in 2007 it was still selling about $30 million a year in the United States. In "Perfumes: The Guide", Luca Turin gave CK One four stars out of five, describing it as a "radiant citrus scent" that combines "soapy, fresh top notes" with heart and base notes simultaneously, creating a linear effect where the fragrance becomes one "chord" maintains rather than changing the smell during the day. It is often regarded as the first "unisex" perfume (although historians note that dividing perfumes by gender is itself a relative novelty, a development of 20th century marketing techniques).

Other projects: In 1997, Morillas and his wife started a line of fragrance sticks called Mizensir, which has expanded to 80 different fragrance sticks. In 2015, Morillas expanded the brand with 17 perfumes. In partnership with Penhaligon's, Morillas also runs a bespoke perfumery service called Bespoke by Alberto Morillas, based in the Salon de Parfum at London's Harrods department store.