He started racing karts as a child and made his car debut in 2002 in the Formula Renault. However, it's with covered-wheel cars that Pier Guidi managed to demonstrate the full extent of his talent. His debut with the Scuderia Playteam in 2005 marks the beginning of a very long sequence of victories in the main European GT championships, at the wheel of the Ferrari 360 Modena GTC.

In 2005 and 2006, he triumphed in the Italian GT Championship, in GT2 and GT1 class respectively. After two fleeting returns with the A1 Grand Prix and Superleague series cars in 2007 and 2008, Pier Guidi continued to succeed in the GT category behind the wheel of the Maserati MC12 and the GranTurismo GT4. He returned to driving Prancing Horse cars in 2011 and, as before, achieved success around the world, including the 24 Hours of Spa-Francorchamps and the prestigious Daytona 24 Hours in 2014. In 2016, he competed on three continents with various Ferrari customer teams and debuted in the 24 Hours of Le Mans alongside Gianmaria Bruni and James Calado, in the AF Corse team’s 488 GTE number 51. He became an official Ferrari driver in 2017 and lived up to the task, becoming WEC GT world champion with James Calado, thanks to three successes achieved with the 488 GTE. He also took part in the Blancpain Endurance Cup for the same team, finishing second in the Monza 3 Hours.

In 2018, Alessandro competed in the FIA WEC Super Season, winning the Silverstone race, and contributed to the success of Mikkel Mac in the International GT Open at the wheel of the Luzich Racing 488 GT3. He also competed in some IMSA races with the Risi Competizione and Scuderia Corsa teams. In 2019, the Tortona driver finished the WEC 2018-2019 Super Season in second place, paired with James Calado, winning the 6 Hours of Silverstone and the 24 Hours of Le Mans. Pier Guidi will take on Season 8 of the WEC with the AF Corse colours, again alongside the English driver, as well as continuing to compete in the European Le Mans Series in the Luzich Racing colours. In the same year, the Italian won the Petit Le Mans with Risi Competizione in the European Le Mans Series with Luzich Racing and took part in FIA WEC Season 8 in the colours of AF Corse, also with James Calado. In 2020, he won the GT World Challenge Europe Endurance Cup, mainly alongside Calado and Nielsen.

The driver from Tortona then enjoyed an extraordinary 2021 that saw him win the world’s most important championships and races. World Champion alongside James Calado for the second time in his career, Pier Guidi triumphed at the 24 Hours of Le Mans and the 24 Hours of Spa-Francorchamps in less than a month. This was crucial to his retaining the GT World Challenge Endurance Cup title. Never before had a driver won the laurel two years in a row. Success in Belgium also opened the door for Pier Guidi to take the Intercontinental GT Challenge title, a championship Ferrari had never previously won. In 2022, the Italian will compete in the World Endurance Championship while at the same time developing the new GT3 and LMH.

Alessandro Pier Guidi retained his World Endurance Championship title alongside James Calado in a season made intense by the development of the 296 GT3 and the 499P. This result gives him three world titles, placing him among the greats of motor racing.