In 1996, he began driving for John Della Penna in both the IRL and Champ Car ranks.

In 2005 following the Indy 500 he retired as a driver and started Hearn Motorsports LLC that ran in the Star Mazda series.

Hearn's parents were also racecar drivers, racing in amateur Sports Car Club of America events on the West Coast.

[4] Hearn then attended the Winfield Racing School at the Paul Ricard circuit in southern France, whose alumni included Alain Prost.

[2][6] In 1997, Hearn and team owner John Della Penna moved full-time to the CART FedEx Championship Series.

[2] In 1999, Hearn crashed coming off turn two on lap four of the Marlboro 500, bringing out the first caution flag of the race.

[9] In 2007, Hearn got a last-minute ride with Jon Herb's backup car with Hemelgarn/Racing Professionals, even though he hadn't raced since the 2005 Indy 500.

Due to this, he became bankrupt and did odd jobs such as driving a forklift, and coached a successful flag football team.

[13][14] In his free time, he does iRacing, a virtual reality racing video game[11] Hearn was married, but they divorced when he got bankrupt.