A painter, engraver and illustrator, Vaccari worked in France and Italy. A pupil of Vespasiano Bignami at the Accademia di Brera in Milan, he travelled to London before starting to work in France around 1901 for periodicals such as Le Monde illustré, and for Le Petit Parisien and Nos loisirs, for which he became, from 1906, one of the principal illustrators. While maintaining ties with the Milanese art scene, he exhibited portraits and animal scenes at the Salon des artistes français, in Paris, from 1907 to 1910. Vaccari lived during this period in Pierrefonds-les-Bains. He also exhibited at the Salon d'Automne in 1910. In 1914 he moved to Genoa, participating in the exhibitions of the Promotrici Genovesi group. He also exhibited in Naples, Turin, Venice, Paris and London. Vaccari's first retrospective as a painter was held in Genoa in 1919, at Palazzo Bianco. Winner of the Premio Ambrosiano in 1922, he participated in the II Biennale di Arti Decorative di Monza in 1925. In 1926 Vaccari opened an art school in Milan dedicated to the study and representation of animals. His production was copious, including advertising posters, book covers, etchings and numerous paintings of animals such as dogs and horses, genre scenes, landscapes. A number of his paintings are preserved at the Galleria d'arte moderna di Nervi, near Genoa.