After winning six national karting championships, Hunter-Reay won a Skip Barber Karting Scholarship to race in Skip Barber Formula Dodge Series. He then won the Skip Barber Formula Dodge National Championship in 1999 and then a shoot-out against the top Formula Dodge drivers for the Skip Barber Big Scholarship prize and its $150,000 prize.
Racing in the Barber Dodge Pro Series from 2000 to 2001, Hunter-Reay won the Rookie of the Year award in 2000, and claimed two wins in 2001. He then proceeded up the Champ Car developmental "ladder" to the Toyota Atlantic Series in 2002, where he finished sixth overall in the points standings, won three races, and led the circuit in laps led, poles, and fast times. This secured him the Worldcom "Rising Star" Award and attention from several Champ Car teams.
In 2003 Hunter-Reay joined the Champ Car World Series, driving for the first-year low-budget American Spirit Team Johansson. Although handicapped with a slower Reynard chassis and three separate engineers, he impressed many with a front row start and third place finish at Mid-Ohio, as well as a win at Surfers Paradise where he qualified as the top Reynard and worked his way up to fifth on a diabolical wet/dry changing track. He opted for a high-risk strategy and pitted on the first lap of a mandatory three lap window to take on slick tires, managing to do what a lot of veterans could not and keep his car on the track and incident free. Through three restarts, he beat first ex-Champion and teammate Jimmy Vasser and then Briton Darren Manning for the win.
In 2004, Hunter-Reay moved to the Herdez Competition team, where he recorded the team's first ever pole and won in dominant fashion at Milwaukee, leading all 250 laps and setting a Champ Car series record for most laps led in a single race. He qualified on the front row at Road America; however, a first-lap back-of-the-track incident where his ex-teammate Vasser forced him off before "RHR" returned the favor at the next corner moved both drivers to dead last. Hunter-Reay fought his way back to a fourth place finish; however, other than at Toronto (where he was running third on the last lap until Patrick Carpentier ran into the back of him and cut down a tire forcing him to pit), the remainder of the season was inconsistent.
In 2005, Hunter-Reay moved again, this time to the uncompetitive second seat at the Rocketsports Racing team. He struggled through most of the season without an engineer and rarely ran near the front of the pack. His rookie teammate Timo Glock was somewhat more successful, almost winning at Montreal with a lucky pit strategy; however, other than that both drivers' best result was a sixth place finish. While Glock would go on to win Rookie of the Year honors, Rocketsports took on a pay driver for the last two races of the season and released Hunter-Reay from the team.
On July 19, Rahal Letterman Racing announced that Hunter-Reay would be replacing Jeff Simmons, who had been dismissed after a series of incidents, in the team's #17 ethanol sponsored car in the Indy Racing League IndyCar Series for the rest of the season. Hunter-Reay began his IRL career with two top 10 finishes, placing 7th at the Honda 200 and 6th at the Firestone Indy 400.
On September 9, Hunter-Reay placed 7th at the Peak Antifreeze Indy 300 - his 3rd Top 10 finish of the season. Despite only starting in six races, his performance was sufficient to win the 2007 Bombadier Rookie of the Year award.
| Year | Team | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | Rank | Points |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2003 | American Spirit Team Johansson | STP Ret | MTY 12 | LBH 7 | BRH 16 | LAU 11 | MIL Ret | LS 12 | POR Ret | CLE 9 | TOR 11 | VAN 6 | ROA 10 | MDO 3 | MTL Ret | DEN Ret | MIA 12 | MXC 11 | SRF 1 | FON -- | 14th | 64 |
| 2004 | Herdez | LBH 7 | MTY 8 | MIL 1 | POR 12 | CLE 11 | TOR 8 | VAN 8 | ROA 4 | DEN Ret | MTL Ret | LS 5 | LVS 13 | SRF 5 | MXC 19 | 9th | 199 | |||||
| 2005 | Rocketsports | LBH 13 | MTY 7 | MIL Ret | POR 15 | CLE Ret | TOR 6 | EDM Ret | SJO Ret | DEN 6 | MTL 12 | LVS 10 | SRF | MXC | 15th | 110 |
| Year | Team | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | Rank | Points |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2007 | Rahal Letterman | HMS | STP | MOT | KAN | INDY | MIL | TXS | IOW | RIR | WGL | NSH | MDO 7 | MIS 6 | KTY 15 | SNM Ret | DET Ret | CHI 7 | 19th | 119 | ||
| 2008 | Rahal Letterman | HMS 7 | STP 17 | MOT1 7 | LBH1 DNP | KAN 18 | INDY 6 | MIL 15 | TXS Ret | IOW 8 | RIR Ret | WGL 1 | NSH Ret | MDO 10 | EDM 8 | KTY 9 | SNM 18 | DET 6 | CHI 9 | SRF2 | 8th | 360 |
| Years | Teams | Races | Poles | Wins | Podiums (Non-win) | Top 10s (Non-podium) | Indianapolis 500 Wins | Championships |
|---|---|---|---|---|---|---|---|---|
| 2 | 1 | 23 | 0 | 1 | 0 | 12 | 0 | 0 |