The 23-year-old driver will be paired with his father, Bobby, the team's co-owner and winner of three championships along with the 1986 Indianapolis 500. Father and son paired together only once before in IndyCar, for a 12th-place finish in the 2010 Indy 500.
Bobby Rahal pulled out of full-time IndyCar racing after the 2008 season. He returned last season and the team nearly won the Indy 500 with Takuma Sato.
Graham Rahal has spent the last two seasons driving for Chip Ganassi. He is expected to be sponsored by TBC Retail Group, which has been with him since 2010.