At international level, he represented Italy on 41 occasions, and took part at the 1984 Summer Olympics and the 1986 FIFA World Cup.
[2][3][4] Bagni played for the Italy national under-21 football team between 1978 and 1980, scoring 5 goals in 12 appearances, including a hat-trick against Greece.
With the under-21 side, he also took part at two UEFA European Under-21 Championships (1978 and 1980), and also at the 1984 Summer Olympics, where Italy finished in fourth place after reaching the semi-final.
[4] He was later included in the Italian 1986 FIFA World Cup squad under manager Enzo Bearzot, however, wearing the number-10 shirt.
[3][4][6][8][9] A generous and hard-working team-player, Bagni was a tenacious, hard-tackling player, with good technique and team spirit, who was usually deployed as central, box-to-box or defensive midfielder throughout most of his career, due to his ability to win back possession and subsequently start attacking plays; his tendency to commit aggressive and reckless challenges, despite his friendly character, earned him the nickname "The Warrior".