Born in Trieste in 1897, Giannino Marchig showed early talent as an artist and at the age of 12, began his formal training in drawing and painting in the studios of prominent artists in Trieste - a city where Italian culture mixed with the Austrian and Northern European taste. In 1915, he moved to Florence and still young, was appointed Professor of Drawing at the Academy of Fine Arts and his work revealed the influence of Florentine artistic life and the Old Masters. He participated in the most prestigious art events of Italy (Stibbert Prize in 1920; 13th Biennale of Venice in 1922; Ussi Prize in 1924) and exhibited widely in Europe and the U.S. In the mid-1930s, with the rise of Fascism, Marchig became disillusioned with the contemporary art scene and suddenly put an end to his artistic career.

At the close of the Second War, Marchig began working as a restorer of paintings. His many visits to Switzerland during the war led him to decided to settle there more permanently. In 1949, he moved to Lausanne, where he found a more peaceful environment to pursue his work as a restorer. In 1961, his move to Geneva offered him the possibility of working closely with the Musée d’art et d’histoire de Genève. In 1969, on the instigation of his wife Jeanne Marchig and inspired by the Carneval of Basel, Marchig returned to the easel. Scenes from the Commedia del Arte dominate this last period of production, a theme of enduring predilection for the artist.

It was only towards the end the of his life and following his death that Marchig's artistic career before his work as a restorer was properly re-appraised, leading to renewed and widespread interest from private collectors and public museums alike. A first important retrospective exhibition was organised in 1980 in Trieste and two important exhibitions of his works were organised at the Musée d’art et d’histoire of Geneva (1985) and at the Gabinetto dei disegni e stampe degli Uffizi in Florence (1994).