|Date of birth||13 October 1959|
|Place of birth||San Marino, San Marino|
|Height||1.78 m (5 ft 10 in)|
|Playing position||Defensive midfielder|
* Senior club appearances and goals counted for the domestic league only.
Bonini was a hardworking and versatile box-to-box midfielder, who was frequently deployed as a central midfielder or as a defensive midfielder during his time at Juventus. Although this position did not allow him the freedom to contribute offensively or creatively that he possessed in his early career, he excelled in his new role as a ball winner, and at breaking down opposition plays, due to his tactical intelligence and positional sense, supporting his more creative team-mates defensively, such as Michel Platini, alongside Marco Tardelli. He was known in particular for his pace and stamina, which earned him the nickname "Platini's lungs", due to his successful partnership in midfield with the Frenchman.
For its 50th anniversary in 2004, UEFA asked each of its 52 member associations to nominate one player as the single most outstanding player of the period 1954–2003, and Bonini was chosen as the Golden Player of San Marino by the San Marino Football Federation in November 2003.
Bonini began his career at Juvenes Dogana in 1973 but failed to make a league appearance during his 4 years at the club. After leaving Juvenes Dogana in 1977, he moved on to join Bellaria, goin on to make 33 appearance scoring 1 goal. After leaving Bellaria in 1978, he moved on to join Forli, going on to make 23 appearances, scoring 1 goal. After leaving Forli in 1979, he moved to Cesena, appearing 60 times and scoring 5 goals.
After leaving Cesena in 1981, Bonini played for Juventus between 1981 and 1988, in which he played 296 matches and scored 6 goals. He won 3 Scudetti, 1 Italian Cup, 1 European Cup, 1 Cup Winners' Cup, 1 European Super Cup and 1 Intercontinental Cup. He is the only Sammarinese footballer to have won an official international title.
Since the San Marino Football Federation was not officially recognised by the Union of European Football Associations (UEFA) until 1990, players from San Marino were assimilated to Italian players. For this reason, Bonini was entitled to play for the Italian Football Federation and actually played for the Italian Under-21 football team. Since he always refused to give up the citizenship of San Marino, he had to wait until 1990 in order to play for San Marino’s first team, winning 19 full caps since then. He played his first match for San Marino against Switzerland on November 14, 1990.
- Serie A: 1981–82, 1983–84, 1985–86
- Coppa Italia: 1982–83
- European Cup Winners' Cup: 1983–84
- European Cup: 1984–85
- European Super Cup: 1984
- Intercontinental Cup: 1985