Visentini was born in Gardone Riviera, in the province of Brescia, and had a brilliant junior career. In 1975, he was both Junior Italian champion and World Champion. As an amateur he won the 1977 Italian time-trial Championship.
He debuted as professional in 1978. In 1980, he won two stages at the Vuelta a España and was ninth overall in the Giro d'Italia. In 1983 Visentini joined the Inoxpran team and was in contention for victory in the Giro with Giuseppe Saronni, but ended up on the podium 2nd place. Riding for the Carrera team in 1984, he won a stage in the 1984 Giro d'Italia and was in a podium position until very late in the race.[1] This race became infamous because French rider Laurent Fignon accused officials of playing favourites by not treating all riders by the same set of rules. Visentini also felt this way making his feelings public.
During the 1984 season he also won a stage in Tirreno–Adriatico and the prologue of the Giro del Trentino.[2] In the 1985 edition, he was in good position to win his first Giro being in the lead for 9 stages when he fell ill and was forced to retire, leaving the victory to Bernard Hinault.
He won the 1986 Giro by defeating racers such as Saronni and Francesco Moser by about 1:00 and 2:00 respectively, and also Greg LeMond who placed 4th. Visentini won stage 6 and took over the Pink Jersey on stage 16 which he would hold for the remainder of the race. In 1987 he played a part in one of the most controversial episodes of 1980s Italian cycle racing: Visentini, who was the racing for Carrera Jeans–Vagabond, took the pink jersey for the leader of the general classification from his teammate Stephen Roche after winning an individual time trial. Several days later in a mountain stage he was suddenly attacked by his teammate Roche, who had ignored the team's order not to attack. The Carrera team led the peloton in the chase after Roche until Visentini was left without any teammates. From there Visentini tried to chase him down on his own but finished several minutes behind the Irishman, who took back the pink jersey.[3] Several days later Visentini had to retire from the race because of a broken wrist.[4]
Roche left the Carrera team, which kept Visentini, but he was never again able to compete at this elite level. He concluded his career in 1990 with 18 victories, including the 1986 Giro d'Italia, the 1981 Giro del Trentino and the 1983 Tirreno–Adriatico.