. Hildebrand made his
IndyCar Series debut in
2010, competing in two races for
Dreyer & Reinbold Racing as a substitute driver for the injured
Mike Conway. On Tuesday, December 14, 2010, it was announced that Hildebrand signed a multi–year contract to drive the No. 4
National Guard entry for
Panther Racing, starting in
2011 after impressing the team during a test. at the
2011 Indy Japan 300. Later in 2011, Hildebrand qualified for the
Indianapolis 500 and was the most successful rookie during his premiere race. Hildebrand was able to lead at the halfway point for Panther Racing and stayed on the lead lap for the entire race. This allowed him to take a gamble during his last pit stop, stretching out his fuel load to an eventual lead on the final lap. On the very last turn, he slid out of the racing lane and into the retaining wall while passing rapidly slowing
Charlie Kimball, allowing
Dan Wheldon to take the victory. Despite the damage to his car – including the loss of a wheel – Hildebrand retained enough speed to cross the finish line in second place. On October 16, 2011, Hildebrand was involved in a fifteen-car chain-reaction crash at
Las Vegas Motor Speedway in the season-ending
IZOD IndyCar World Championships. He sustained an injured sternum and was transported by ground ambulance to a Las Vegas area hospital, where he was admitted for treatment. The crash claimed the life of two-time Indy 500 winner and
2005 IndyCar Series champion Dan Wheldon. Following a last-place finish in the
2013 Indianapolis 500, Hildebrand was released by Panther Racing. He had announced earlier in the year that he would be running selected
Formula DRIFT races as a teammate to
Tyler McQuarrie. In 2014, Hildebrand joined
Ed Carpenter Racing for the
Indianapolis 500, driving the No. 21. On November 4, 2016, it was confirmed that Hildebrand would take over the Ed Carpenter Racing No. 21 car for the 2017 season, replacing
Josef Newgarden. He finished 15th in the points standing for the season, achieving a second-place finish in
Iowa and a third in
Phoenix. Following the season Hildebrand was not retained by the team. For 2018, Hildebrand was signed for by
Dreyer & Reinbold Racing to pilot their car in the Indy 500 (their only entry of the season) and finished eleventh. He returned in the same role in 2019, finishing twentieth. He again returned in 2020 for the same one-race role, despite the team's increased commitment to a part-time schedule. He finished in 16th. In 2021, Hildebrand drove a specially liveried car for
A.J. Foyt Enterprises, commemorating the sixtieth anniversary of team owner
A.J. Foyt's first of four
Indianapolis 500 wins. He finished in fifteenth place. ==Pikes Peak Hillclimb==