After the Grand Prix of Long Beach, Rahal was signed to drive for his father's team, Rahal Letterman Racing, in the 2010 Indianapolis 500. Rahal qualified in the seventh position for the race, and finished 12th. On June 10, 2010, Dreyer & Reinbold Racing announced the signing of Rahal for the Iowa Corn Indy 250 at Iowa Speedway, filling in for the injured Mike Conway in the No. 24 entry on a one-off basis. Rahal returned to Newman/Haas Racing for 6 of the remaining 8 races of the 2010 season, starting with Toronto and returned to Sarah Fisher Racing for the Kentucky Speedway race. Rahal's 2010 totals included 12 starts for four teams and a 20th-place finish in points.