Filippi made the step out of karting in 2003, competing in Formula Renault 2.0 Italia, where he finished third in 2004 behind Pastor Maldonado and Kohei Hirate.

In 2007, he continued in GP2 with Super Nova Racing and emerged as one of the series' top performers, finishing the season in fourth position.

[1] On 6 December Filippi tested for Super Aguri F1, being even faster than regular race driver Takuma Sato.

Filippi drove for the ART Grand Prix team in the first half of the 2008 GP2 Series season, alongside Romain Grosjean.

Filippi began the 2010 GP2 Series season without a drive, but returned to Super Nova mid-season to replace the injured Josef Král.

During this period, Filippi became the most experienced GP2 driver in the series' history, beating Javier Villa's record of 82 race entries.

He returned to the series the following year, taking one pole position, three fastest laps, one win and five further podiums, finishing as runner-up to Kevin Ceccon by only 3 points despite having missed two races.

On 6 March 2012, it was announced that Filippi would join Rahal Letterman Lanigan Racing in the IndyCar series from the Indy 500 onwards.

A few days before the GP of Indianapolis, Coyne excluded Filippi from both Indy events and signed Gabby Chaves in place of the Italian driver.

2017 saw Filippi join Nio in the all-electric FIA Formula E Championship alongside Oliver Turvey,[11] where he picked up a point in his debut race with a tenth place finish in the 2017 Hong Kong ePrix.