Although he struggled with consistency, Phillippe often qualified and ran mid-pack, outpacing the more highly regarded Ranger towards the end of the year.

While driving for Conquest in 2005, Philippe was voted by his peers as the Bosch Most Improved Driver in the Series, and won the award in 2006 as well.

For the 2006 season, Philippe moved to CTE-HVM Racing and earned his first podium finishes at Milwaukee and Montreal before claiming his first victory at Surfers Paradise.

With his victory at Surfers Paradise, Philippe became the youngest winner in Champ Car World Series history, and again being awarded most improved driver in 2006.

But on October 3, 2007 it was announced that Nelson Philippe would return to Champ Car and drive for his former team, Conquest Racing.

It's been a challenge to be sidelined this year, but things happen for a reason and right now it's full steam ahead for Australia and Mexico."

He also competed in the opening round of the 2008–09 GP2 Asia Series season for ART Grand Prix before being replaced by Pastor Maldonado.