A former centre back who played several seasons for his beloved team, AS Roma, other than Spal and Ascoli, where he played for nine season, Mazzone left the playing career in season 1968-1969, to become the manager of Ascoli itself, in Serie C.
Already popular because of his playing history for the team, Mazzone gained even more popularity by leading the team for twelve years, up to the first Serie A appearance in the team history. Successively, Mazzone coached several Serie A and Serie B teams, such as Fiorentina (his personal best result, third-placed in 1976/1977), Catanzaro, Bologna F.C. 1909, Lecce, Pescara and Cagliari, that he led to the first appearance in a European competition since the Riva's times.
After his successes at Cagliari, Mazzone fulfilled his dream, being called to coach AS Roma for the season 1993/1994. He remained at the helm of AS Roma for three season, however without being able to obtain any notable triumph.
He then went back to Cagliari, then coached Napoli, Bologna again, Perugia, and Brescia, where he had the opportunity to have Roberto Baggio among his players. Mazzone was at the centre of controversy when, on September 30, 2001, during a league match against team rivals Atalanta, after his team tied the score in the final minutes, he ran for about 70 meters and screamed towards the Atalanta supporters, guilty of having offended him for all the match long with personal insults.
Mazzone left Brescia in 2003 in order to coach Bologna for the third time on his long career. However, his adventure lasted only two season, as the team was surprisingly relegated in Serie B at the end of the 2004/2005 season. It was the first relegation ever in Mazzone's career, and it convinced him to take a break for a while.
However, on February 7, 2006, at the age of 68 years and 11 months, Mazzone accepted an offer of Livorno for filling the coaching office left vacant by Roberto Donadoni, who resigned the day before. He left the job at the end of the season.