Rahal was born in Columbus, Ohio. He attended New Albany school systems in Ohio and graduated in June 2007 with plans to attend Denison University. Rahal is a die-hard Ohio State fan and enjoys NHL hockey and golf. He is a car enthusiast and owns a growing Ducati collection.

Rahal is married to former NHRA drag racer Courtney Force, daughter of 16-time NHRA drag racing champion and legend John Force.[13] In May 2020, the pair announced they were expecting their first child; in November she gave birth to a daughter, Harlan Ann Rahal.[14]

Rahal started the Graham Rahal Foundation in 2009 to support Alex's Lemonade Stand for Childhood Cancer and The Association of Hole in the Wall Camps (known as SeriousFun Children's Network as of April 2012).[15] In 2019, Rahal and wife Courtney Force took on the foundation in a joint effort, changing the name to Graham & Courtney Rahal Foundation (GCRF). GCRF supports Turns for Troops, benefitting the national nonprofit SoldierStrong, and Colorado State University's One Cure.