Sandri was part of the cultural and literary scene of Milan and he collaborated with Giovanni Scheiwiller and Cesare Branduani at the Hoepli bookshop.
His precocious and extraordinary talent in drawing won him the "Nude Award" at the Fine Arts Academy of Brera when he was only 20. At the age of 24 he did some illustrations for "Qua e là per il Mondo" by Luigi Barzini, published by Hoepli. During his career as an illustrator he came into contact with Achille Beltrame, Riccardo Salvadori, Anselmo Bucci, Riccardo Galli and others.
Between the ages of 22 and 25 years old he was making contributions to magazines of the "Il Corriere della Sera" group: first with "La lettura" then on "Il Corriere dei Piccoli" and "Italia Bella". He also prepared drawings (inedited) for "Pluto" a Greek play by Aristotles.
Between the ages of 29 and 30 he did illustration for "Il "Fanciulli d'Italia" by A.V.Gentile, "Viaggio Sentimentale" by L. Sterne and also for "Il Novellino" and "Il Guerin Meschino" . At 31 years old Hoepli gives him the big job of illustrating of "Poesie edite e inedite" by Carlo Porta .
At 32 his career is abruptly interrupted by the sad event of his illness .
Later on he prepares sketches for "Lazzarillo de Tormes" (a seventeenth century Spanish literature masterpiece), other sketches, which he had been working on for years, for the book "I promessi sposi" by Alessandro Manzoni and a rough draft of the manuscript "Cosa è La Follia". He also does drawings and a rough draft for "The Prayers" of St. Francis (a famous thirteenth centry text). He also cooperates with the publishing house Ceschina for the publication of some children's books including the drawings for "Enzeli", all of which remain unpublished.
The critic and art historian Gian Alberto Dell'Acqua writes in a review for Il Corriere della Sera on 22.01.1986 in the introduction to the monograph "A Tribute to Gino Sandri", 1998:
«Sandri's drawings are extraordinary as far as graphic design goes and many of his illustrations show this. He catches people and situations in a very characteristic way . We are struck by his exceptional and wonderful choice, often an innovation, of the passages he illustrates, by the effectiveness of his graphic concisiveness and of his composition».
