Regarded as one of the greatest managers of all time,[1] he is famous for having been one of the most successful head coaches in Italy, winning several domestic and international titles during his tenure with AC Milan.

[3][4] Rocco made an appearance for the Italy national team on one occasion: in Vittorio Pozzo's selection in the 1934 FIFA World Cup qualification match, on 25 March 1934 against Greece, a 4–0 home victory.

[4] During his time with Padova, he also coached the Italian team at the 1960 Summer Olympics in Rome, alongside Giuseppe Viani, where they finished in fourth place.

[4] In 1961, Rocco was appointed as new A.C. Milan coach, starting one of the most successful periods for the rossoneri: he built a hard-working and defensively sound side around the team's young star playmaker, Gianni Rivera, which complemented the midfielders' creative playing style; Rocco formed an important relationship with Rivera throughout his career, and together, they played a key role in the club's successes,[7] winning the Italian league in 1962 and the European Cup in 1963.

His teams were known for their work-rate and physicality, as well as their simple but effective and pragmatic tactical strategies, namely their defensive strength, ability to counter–attack quickly with long balls, and score goals after winning back possession, rather than for being aesthetically pleasing to watch.

[15] Rocco's tactics heavily influenced manager Giovanni Trapattoni, who became one of the main proponents of the zona mista ("mixed zone," in Italian), or gioco all'italiana, which drew elements from both man-to-man marking systems such as Italian catenaccio, and zonal-marking systems such as Dutch total football.