During his career he also used several pseudonyms, including Stelio Martelli, Eugenio Ventura, Piero Selva, Mungo Graham Alcesti and T. Maggio.

Born in Pavia, Milani debuted as a writer in 1952 and wrote over two hundred books, spanning children's and adult novels, collections of short stories, biographies and historical books.

[2] Among his best known works are the giallo-crime novel cycle featuring police commissioner Melchiorre Ferrari, the series of western novels Tommy River, and Fantasma d'amore, a novel adapted into a film with the same name by Dino Risi, starring Marcello Mastroianni and Romy Schneider.

[2][3][4] Milani was also well known as a comic writer, mainly active for Corriere dei Piccoli and Corriere dei Ragazzi, whose collaborations include Hugo Pratt, Milo Manara, Sergio Toppi, Dino Battaglia, Aldo Di Gennaro [it], Arturo del Castillo, Mario Uggeri, Grazia Nidasio, and Attilio Micheluzzi.

[4][5] As a journalist, Milano worked for important publications such as Corriere della Sera and La Domenica del Corriere, and was editor-in-chief of the daily newspaper La Provincia Pavese.