In 1949 he won a scholarship awarded by the Dutch government to study in Amsterdam under the neo-plastic painter Friedrich Vordemberge-Gildewart.
[2] In 1955 he began a twenty-five-year collaboration with the Schneider Gallery in Rome, alongside such artists as Corrado Cagli, with whom he has been frequently associated.
In 1979 he left Rome to settle in New York City, where he taught at the Cooper Union School of Art from 1984 to 2014.
Dino Buzzati wrote in 1968 that “just as on the same wall paintings by different artists can, perhaps through violent contrasts and contradictions, merge in a fortunate harmony, so Vanni gathers in the same canvas two, three, four sections which, considered in isolation, may seem to be by different authors.”[8] Thereafter, transposing this approach from space to time, Vanni projected his abstract films on translucent bas-reliefs, then returned to painting on canvas with works that stressed the contrast between texture, color, and drawing until his departure for New York in 1979.
[8] Art critic Giorgio di Genova writes about Vanni's American paintings: “Everything is something else, every substance is appearance, and appearance is painting, a sumptuously bejeweled art of formal and technical inventions.”[1] Vanni also illustrated several books, including Agostino by Alberto Moravia, Love by Lowell A. Siff, and The Magic Chalk by Zinken Hopp, for which he won in 1958 the “Oscar de l'Album”, awarded by the Club des Lecteurs, Paris.