After debuting for the national team in 1925 he eventually won the left back position from Umberto Caligaris before their 1934 World Cup qualifying match against Greece. Vittorio Pozzo started him in every match, helping the Azzurri win the title. However, the part of his career that stands out is the corruption scandal in the Torino-Juventus derby in 1927 that resulted in Torino being stripped of their title. A manager from Torino offered Allemandi 50,000 lira to throw the game, 25,000 immediately and the rest after the match. Torino won the match 2–1, but when Allemandi went to collect the rest of the money he was refused. The confrontation was overheard by a journalist from the Tifone newspaper who then went public with the information. Along with Torino's title revocation, Allemandi was banned for life. He was later pardoned by Umberto of Savoy in 1928 and joined Ambrosiana-Inter.