Born on Sardinia, Antonio Cossu eventually settled in Brussels, Belgium. While studying at the Saint-Luc in Brussels, he published his first work in magazines like Curiosity Magazine and Spatial. At the Saint-Luc's Atelier R, he cooperated on the third edition of Le Neuvième Rêve, for which he created a first version of 'Boskovich'. After a brief appearance in Aïe!, he made his debut in Spirou with the series 'Alceister Crowley' in 1980.
He drew his first album for Deligne ('Sang Anesthésié), while also creating several short stories for Le Journal Illustré, Métal Hurlant, Tintin and Pilote. Several of these short stories were collected in the album 'No Man's Land', at Les Humanoïdes Associés in 1984.
Cossu teamed up with Philippe Berthet to start the futuristic series 'Le Marchant d'Idées' in Circus in 1982. Cooperating on both the scenario and the artwork, Cossu and Berthat also created several short stories, that are collected in the album 'Rêves de Chien'. He also continued to work for Spirou, where he produced a second version of 'Boskovich', and illustrated several dark stories with text by Jamsin (collected in the album 'Histoires Alarmantes'). Cossu relaunched 'Alceister Crowley' together with text writer Louis Savary at the publishing house Alpen in 1990. In 1993, Cossu co-founded Oro Productions with Philippe Foerster, and launched the magazine Brazil. with text by Rodolphe, he began the series 'Angie' at Casterman.