Giovanni Pettenella joined the Italian national cycling team in 1961 and garnered attention the following year when he won two European titles and one national one in the individual sprint. He followed this up with a gold medal in the tandem event at the 1963 Mediterranean Games, alongside Sergio Bianchetto. His greatest achievement, however, came at the 1964 Summer Olympics, where he surprised the crowd to win gold in the sprint and silver in the 1,000 metres time trial. He was also first in the tandem event at the Italian National Championships that year, alongside Giordano Turrini. He turned professional after the Games and won a bronze medal in the individual sprint at the 1968 UCI Track Cycling World Championships. He also set a world trackstand record of one hour and five minutes at the national championships that year, which remained a record at the time of his death.
After retiring from active competition in 1975, Pettenella operated a popular bicycle shop and worked as a technical commissioner at a velodrome until 1987. He also served as a coach with the national team. He kept his store operating until his death in February 2010, at the age of 66.
Italy