Sisinnio Usai was born in the Asinara island in 1950. He attended the Art Institute of Sassari, where he had as teacher Gavino Tilocca and Stanis Dessy .
His exhibitions started in Sassari in 1971, the first exhibition he held was presented in a catalog by Mario Delitala. From 1979 to 1981 he illustrates the stories of Enzo Espa which were published in books, newspapers and periodicals.
Since 1988 he starts his collaboration with Caddhos magazine and the publisher Soter providing graphic and pictorial illustrations. In the 80s and 90s those were assigned several times on posters of major folklore, cultural and regional trade events. Many of his works were also produced for public institutions and private collectors .
From 1992 he teaches artistic anatomy at the Fine Arts Academy in Sassari .