He was elected in 1948 to the Chamber of Deputies, becoming briefly Minister of Public Education in 1954, under Christian Democrat Mario Scelba.

[1] He maintained his Ministry also during the Antonio Segni's Cabinet (1954-1957), but was finally removed from office by new Prime Minister Adone Zoli.

[2] As Minister of Foreign Affairs, Martino promoted a better European integration and internationalism, first with the Messina Conference in 1955.

In the same year Martino, along with Halvard Lange from Norway and Lester Pearson from Canada, became a "sage" of the NATO, promoting its involvement in civil areas.

In 1994, with discovery in a military base of an armoire with secret documents on Nazi war crimes in Italy, nickname "Armoire of Shame" ("Armadio della Vergogna"), emerged that Martino blocked the investigations to avoid German isolation during Cold War.