Born in the Bovisa district of Milan, Bagnoli began his professional career as a midfielder with his hometown club Milan in 1955. Although he struggled to break into the starting line-up, due to the presence of several talented players in the first team, he was able to make his top flight debut with the club in his first season and subsequently won both the Serie A title and the Latin Cup during the 1956–57 season. He later joined Verona in 1957, where he became an important figure with the club. In his first season he scored 3 goals in 23 appearances, although he was unable to prevent the club's relegation to Serie B. In the following three seasons however, he excelled, scoring 25 goals in 74 appearances in Serie B. He later had two separate season long spells with Udinese, which were separated by two three seasons stints at Catanzaro and SPAL respectively. He ended his career in 1973, with Serie C side Verbania.