Born in Mantua in 1947, Sozzani graduated from Bocconi University, Milan. While attending University in the late 1960s/early 70s, she began working as an editor for several Italian fashion magazines. During the following decade, Sozzani was editor-in-chief for all Italian Vogue's special issues working with photographers and artists Sarah Moon, Herb Ritts, Bruce Weber, Paolo Roversi, Robert Mapplethorpe, William Wegman and Deborah Turbeville.
In 1986, Sozzani left Italian Vogue and was appointed by Alexander Liberman as editor-at-large for American Vogue for Italy.
In 1987 Sozzani launched Italian Elle as editor in chief. In 1989 Sozzani met American artist Kris Ruhs, beginning a collaboration in both their lives and work. In 1990 she founded Galleria Carla Sozzani at 10 Corso Como in Milan.
Her first published book was on Walter Albini, and was followed by books on Pierre Cardin, Rudi Gernreich, Paco Rabanne and photography catalogs. She subsequently oversaw more than 250 exhibitions of photography and design, showcasing the works of artists including Man Ray, Horst, Annie Leibovitz, Helmut Newton, David La Chapelle, Jean Prouvè, Marc Newson, Shiro Kuramata, Loretta Lux and Robert Polidori.
In 1991, other spaces within 10 Corso Como joined the Galleria, including a fashion and design store, an expanded bookstore, a café restaurant with city garden, a hotel named Three Rooms and a roof garden.
In 2001, Sozzani edited Talking to Myself, with Yohji Yamamoto, which she co-published with Steidl. She curated the photography exhibition at the MEP in Paris. In 2002, she opened 10 Corso Como Comme des Garçons in Tokyo, a co-venture store with Rei Kawakubo.
In 2008, in a joint venture with Samsung Group, she created 10 Corso Como in Seoul, a three-store location combining fashion, art, design and cuisine, designed by Kris Ruhs.
On 31 March 2012, 10 Corso Como opened its second location in Seoul - 10 Corso Como at Avenue L, also designed by Kris Ruhs.
Franca Sozzani (1950-2016), longtime editor-in-chief of Vogue Italia, was her sister.