In his second year of Pro Series competition, Thiago Medeiros won the championship convincingly, giving Sam Schmidt Motorsports its first title.

Medeiros became champion by taking the green flag at the penultimate round in Chicagoland, and finished with a 134-point lead over Paul Dana, who scored his lone Infiniti Pro Series win at Milwaukee.

Despite a penalty at the last round that demoted him behind Arie Luyendyk Jr. in the standings, Chesson won Rookie of the Year over Leonardo Maia by 25 points.

While the Freedom 100 attracted 17 competitors, the Infiniti Pro Series struggled with entries throughout much of 2004, especially during the summer stretch, with only nine cars and just three finishers at the Milwaukee round.

Former IndyCar drivers that competed during the season were Billy Roe, Jon Herb, Cory Witherill and Scott Mayer.