In 1937, he was in Paris, where he exhibited at the Salon des Jeunes; then in 1940 with his brother Xavier, he moved to Italy.
After a Post-Impressionist experience, immediately after World War II he joined the school of Armenian artist Gregorio Sciltian, painting trompe-l'œil work.
With Pietro Annigoni and his own brother, Bueno took part in the "Pittori moderni della Realtà (Modern Painters of Reality)" group .
[1] A dynamic and restless experimenter, after these experiences he conducted in-depth research in genres: abstract painter in 1950–53 while working as secretary for the Numero magazine; neometaphysic painter with his clay pipe series in 1953–57; verist; materiologic as a follower of Informale with a number of imprint forms in 1960–62; signaletic and pop in the middle of the 1960s; neodada and visual painter – all this as an eternal combinative play of subjects and materials.
[2] Bueno's final affirmation occurred at the Biennale di Venezia of 1984, a few months before his death, when he was already gravely ill: he exhibited a series of magistral work that was highly acclaimed and undoubtedly represents the apex of his whole production.